Further characterization of stimulus interaction of cat carotid chemoreceptors

Cellular as well as humoral immune reactivity were studied in healthy young (< 30 years; n = 12) and older (> 65 years; n = 12) individuals before as well as 1 month after immunization with a trivalent whole virus influenza vaccine. Before vaccination, peripheral blood mononuclear cell proliferation in response to in vitro stimulation with each of the virus strains was low in both groups. No antibodies against either the H1N1 or the B strain were found in most individuals, while 91% of the young and 75% of the elderly persons had low but protective antibody titres to the H3N2 strain. Vaccination led to a significant enhancement of peripheral blood mononuclear cell reactivity to all three influenza strains in both age groups. However, there was a significant difference in the humoral immune response between the groups. While there was a vigorous antibody response to all three vaccine strains among young persons, protective titres against the H1N1 and the B strains were only just reached in the old. In contrast, antibody production to the H3N2 strain was most abundant in the majority of elderly individuals, leading to significantly higher titres in the old than in the young group. In conclusion, the results demonstrate the preferential induction of antibodies to one particular influenza strain despite equal T cell recruitment to all vaccine strains in healthy aged individuals after immunization with a trivalent influenza vaccine. Our findings underline the complexity of immunological alterations to be expected after vaccination in healthy elderlies.     

Resistance to and recovery from lethal influenza virus infection in B lymphocyte-deficient mice

In the adaptive immune response to most viruses, both the cellular and humoral arms of the immune system play complementary roles in eliminating virus and virus-infected cells and in promoting recovery. To evaluate the relative contribution of CD4+ and CD8+ effector T lymphocytes in virus clearance and recovery, we have examined the host response to lethal type A influenza virus infection in B lymphocyte-deficient mice with a targeted disruption in the immunoglobulin mu heavy chain. Our results indicate that naive B cell-deficient mice have a 50- 100-fold greater susceptibility to lethal type A influenza virus infection than do wild type mice. However, after priming with sublethal doses of influenza, immune B cell-deficient animals show an enhanced resistance to lethal virus infection. This finding indicates that an antibody-independent immune-mediated antiviral mechanism accounts for the increased resistance to lethal virus challenge. To assess the contribution of influenza-specific CD4+ and CD8+ effector T cells in this process, defined clonal populations of influenza-specific CD4+ and CD8+ effector T cells were adoptively transferred into lethally infected B cell-deficient mice. Cloned CD8+ effectors efficiently promoted recovery from lethal infection, whereas cloned CD4+ T cells conferred only partial protection. These results suggest that memory T lymphocytes can act independently of a humoral immune response in order to confer resistance to influenza infection in immune individuals. The potential implications of these results for vaccination against human influenza infection are discussed.     

Evaluation of live, cold-adapted influenza A and B virus vaccines in elderly and high-risk subjects

We have evaluated the use of live cold-adapted influenza A and B virus vaccines in the elderly. Cold-adapted influenza A and B virus vaccines are safe and modestly immunogenic in individuals over 65 years of age. However, our studies and those of other groups have shown that immune response to cold-adapted vaccines in this age group are modest. Administration of combined cold-adapted influenza A and inactivated influenza vaccine has resulted in slightly higher frequencies of local and systemic humoral immune responses than inactivated vaccine alone in some, but not all, studies. In a double-blind field trial conducted in nursing homes over a 3 year period, combined cold-adapted influenza A (H3N2) and trivalent inactivated influenza vaccine resulted in a 60% decrease (95% CI, 18-82%) in the rate of laboratory documented influenza A compared with inactivated vaccine alone. Further studies of multivalent cold-adapted influenza vaccines used in combination with inactivated vaccine should be performed.     

The influence of sequential annual vaccination and of DHEA administration on the efficacy of the immune response to influenza vaccine in the elderly

The present study examined the effect of repeated vaccination and of dehydroepiandrosterone (DHEA) treatment on the immune response to influenza vaccine in elderly subjects. Seventy-one elderly volunteers, aged 61-89 years, enrolled in a prospective randomized, double-blind study to receive either DHEA (50 mg qd p.o. for 4 consecutive days starting 2 days before immunization) or placebo. Antibody response against the three strains of vaccine was measured before and 28 days after vaccination, and compared between previously vaccinated and non-vaccinated subjects. DHEA treatment did not enhance established immunity. A significant decrease in attainment of protective antibody titer (titer of 1:40 or greater) against A/Texas in subjects with non-protective baseline antibody titer was recorded following DHEA treatment compared to placebo (52 vs. 84%, P < 0.05). Post-immunization titers against influenza A strains were significantly higher in those subjects who were never immunized before. Additionally, post-vaccination protective titers against the A/Johannesburg strain were more prevalent in those subjects who were never vaccinated before. The results were not the same for anti-B/Harbin antibodies-repeated vaccination caused a non-significant increase in HI titer in previously vaccinated subjects.     

Immunogenicity of pneumococcal vaccine in persons with spinal cord injury

OBJECTIVE: To determine immunogenicity and optimum timing for administering the 23-valent pneumococcal vaccine after spinal cord injury (SCI). DESIGN: Double-blind, randomized, placebo control study. SETTING: SCI unit in a tertiary care medical center and community. PARTICIPANTS: Eighty-seven persons with recent SCI. INTERVENTION: Participants were randomized to receive either placebo or pneumococcal vaccine at 16 to 18 days versus 4 to 6 months postinjury. MAIN OUTCOME MEASURES: Antibody concentrations were measured prior to intervention and 1, 2, and 12 months afterward to evaluate the immune response to five serotypes of Streptococcus pneumoniae. Effects of demographic and injury-related variables on immune response were also evaluated. RESULTS: Timing of vaccination did not influence mean antibody concentrations for any serotype (p > .05). Ninety-five percent of vaccinated persons had twofold or greater increases in antibody concentration for at least one serotype when measured 1 month after vaccination versus 35% of placebo groups (p < .01). After 12 months, 93% of vaccinated persons in both groups maintained antibody concentrations twofold or greater than baseline values. CONCLUSIONS: Most participants developed an immune response to at least one serotype that was maintained for at least 12 months. Immune response varied according to serotype. Given the favorable immune response and no effect of timing, persons with SCI should receive pneumococcal vaccine during initial hospitalization.     

The importance of MHC-I and MHC-II responses in vaccine efficacy against lethal herpes simplex virus type 1 challenge

To investigate the importance of major histocompatability complex (MHC) class I- and MHC class II-dependent immune responses in herpes simplex virus-1 (HSV-1) vaccine efficacy, groups of beta 2% (MHC I-) and Ab% (MHC II-) mice were inoculated with various vaccines, and then challenged intraperitoneally with HSV-1. Following vaccination with either live avirulent HSV-1, expressed HSV-1 glycoprotein D (gD), or a mixture of seven expressed HSV-1 glycoproteins (7gPs), Ab% (MHC-II-) mice developed no enzyme-linked immunosorbent assay (ELISA) or neutralizing antibody titres. In contrast, significant ELISA and neutralizing antibody titres were induced in beta 2m% (MHC-I-) mice by all three vaccines. The neutralizing antibody titres were similar for all three vaccines, but were only approximately 1/4 to 1/3 of that developed in C57BL/6 (parental) mice vaccinated with the same antigens. All three vaccines protected 100% of the wild-type C57BL/6 mice against lethal challenge with 2 x 10(7) plaque-forming units (PFU) of HSV-1. The live virus vaccine and the 7gPs vaccine also protected 80% of the beta 2m% mice against the same lethal HSV-1 challenge dose. In contrast, in Abo/o mice, none of the vaccines provided significant protection against the same lethal challenge dose of HSV-1. However, at a lower challenge dose of 2 x 10(6) PFU, all three vaccines protected 70-80% of the vaccinated Ab% mice (compared to only 10% survival in mock vaccinated controls). Thus, vaccination provided some protection against lethal HSV-1 challenge in both beta 2m% and Ab% mice; however, the protection was less than that seen in the parental C57BL/6 mice. In addition, Ab% mice were less well protected by vaccination than were beta 2m% mice. Our results suggest that (1) both MHC-I and MHC-II are involved in vaccine efficacy against HSV-1 challenge; (2) both types of responses must be present for maximum vaccine efficacy: and (3) the MHC-II-dependent immune response appeared to be more important than the MHC-I-dependent immune response for vaccine efficacy against HSV-I challenge.     

An early humoral immune response in peripheral blood following parenteral inactivated influenza vaccination

The enzyme-linked immunospot assay was used to examine the humoral immune response in 15 healthy volunteers immunized with either split or subunit inactivated trivalent influenza vaccine containing A/Beijing/353/89 (H3N2), A/Taiwan/1/86 (H1N1) and B/Yamagata/16/88. The rapidity of the individual B-cell and serum antibody response was examined in lymphocyte and serum samples collected at various time intervals after vaccination. A rapid serological response was detected with increases in antibody titre detected in the majority of volunteers by 7-8 days postvaccination. Influenza-specific plasma cells were detected as early as 4 days postvaccination, higher numbers of IgA and IgG antibody-secreting cells (ASC) were observed which peaked at 7-8 days postvaccination. The number of ASCs then declined, with low numbers of cells detected at 11 days postvaccination. Influenza-specific IgA ASCs were predominantly of the IgA1 subclass. This rapid immune response may have a bearing on future vaccination policies of unimmunized 'at risk groups' in times of high influenza activity.     

Listeriolysin and IrpA are major protein targets of the human humoral response against Listeria monocytogenes

We have examined the human humoral immune response directed against proteins of Listeria monocytogenes in both healthy individuals and listeriosis patients. Two major targets for an antibody response were found in individuals that did not suffer from listeriosis: listeriolysin (Hly) and the recently described internalin-related protein (IrpA). In contrast, the humoral response in listeriosis patients appears to be more heterogeneous and included Hly, IrpA, InlB, and ActA as major targets.     

Recurrent intracranial neurenteric cysts

To determine the efficacy of a single influenza vaccine administration in the elderly receiving annual influenza vaccination, antibody response to influenza vaccine was compared between once and twice injections in a geriatric cohort. Influenza vaccination had been done for 69 inpatients in the year prior to the study, and was administered twice for 34 of them and once for the other 35 during the study period. Influenza vaccine was injected twice to 77 inpatients who had not received influenza vaccine in the year prior to the study. Hemoagglutination inhibition (HI) antibody titer for influenza A/H1N1, A/H3N2, and B was measured before vaccination, after the first vaccination, after the second vaccination, and after the epidemic period, September 1995 to April 1996. HI antibody titer prior to vaccination was significantly higher in the patients who had received influenza vaccination the previous year. The influenza vaccine induced an increase in HI titer in almost all subjects, and the geometric mean of the HI titer after vaccination in the patients who received vaccine once was comparable to that of the patients injected vaccine twice. The number of patients with HI titers of over 128x increased, and the frequency ranged from 60.0% to 97.1% for the influenza viruses of the three subtypes. The frequency of HI titers over 128x was not significantly different among the three groups. The second vaccination did not increase the number of patients with HI titers over 128x when compared with the number after the first injection in the patients who had received influenza vaccine the previous year. These results suggest that prior vaccination does not diminish the antibody response to influenza vaccine in the elderly. The efficacy of a single influenza vaccination is comparable to that achieved by twice injections in the elderly receiving annual influenza vaccination.     

Immunosuppression in paracoccidioidomycosis: T cell hyporesponsiveness to two Paracoccidioides brasiliensis glycoproteins that elicit strong humoral immune response

To assess human cellular immune response to paracoccidioidomycosis (PCM), lymphocyte proliferative responses to purified antigens from Paracoccidioides brasiliensis were determined in healthy persons previously infected by the fungus (positive donors), in healthy noninfected persons (controls), and in PCM patients. Affinity-purified gp70 and gp43, the two major antigens in humoral immune responses, were used. Both induced lymphocyte proliferation (gp43 species-specific) in positive donors but not in controls; healthy persons previously infected by Histoplasma capsulatum reacted to gp70 and not to gp43. A similar cross-reactivity in antibody response to gp70 was previously reported; however, antibody response to gp43 has been considered specific. Lymphocytes from PCM patients, who, unlike positive donors, have high levels of anti-gp43 and anti-gp70 antibodies, proliferated poorly with gp70 and gp43 but better with other stimuli. This dichotomy between humoral and cellular antigen-specific responses suggests a Th2 immune response in PCM, which may be related to failure to control the infection.     

Clinical and serological responses to an inactivated influenza vaccine in adults with HIV infection, diabetes, obstructive airways disease, elderly adults and healthy volunteers

To investigate the clinical and serological responses to an inactivated influenza vaccine (split-virion A/Singapore/6/86-like strains H1N1 (15 ug HA), A/Beijing/353/89-like H3N2 (15 ug HA) and B/Yamagata/16/88-like strain (15 ug HA): MFV-JECT, Merieux, UK) in persons with HIV infection, diabetes, obstructive lung diseases, elderly adults and healthy volunteers. Forty-nine HIV-infected persons received 2 doses of the vaccine at one-month intervals; 34 healthy volunteers, 30 elderly persons, 29 with insulin and non-insulin diabetes and 14 with obstructive airways diseases were vaccinated with one single dose between October 1992 to January 1993. Serological testing of antibody responses was done using haemagglutination assay. Beta2-microglobulin in HIV-infected persons was measured using radioimmunodiffusion between 1st and 2nd dose. Fructosamine levels in diabetic persons were assessed for diabetic control and peak expiratory flow rate (PEFR) was self monitored in persons with lung diseases. All groups apart from the elderly filled in a symptom score chart for the first 5 days following vaccination. A 4-fold rise in titre equal to or more than 1:64 to all the 3 antigens occurred in 20 (58.8%) of healthy volunteers compared with 13 (44.8%) diabetics, 5 (35.7%) with lung diseases, 10 (33.3%) elderly and 13 (26.5%) with HIV infection. A significant correlation of serological response to number of CD4 count in persons with HIV infection was noted (H1N1 P=0.0013, H3N2 P=0.025, BYAM P=0.0018). Mean beta2-microglobulin levels did not change significantly post 1st and 2nd vaccination. Mean fructosamine level did not change significantly. There was no significant change in PEFR. The vaccine was well tolerated. Persons with HIV infection and low CD4 count do not serologically respond well to influenza vaccine even with 2 doses compared to the other 4 groups. The other 4 groups had adequate protective serologic responses. The vaccine was well tolerated in all groups.     

Comparison of chagasic and non-chagasic myocardiopathies by ELISA and immunoblotting with antigens of Trypanosoma cruzi and Trypanosoma rangeli

Trypanosoma cruzi associated myocardiopathy, or Chagas disease, continues to be a serious problem in Venezuela, for which there is neither a vaccine nor a cure. In order to learn more about the humoral immune response to trypanosomal antigens, and to try to identify dominant antigens, we used ELISA and immunoblotting to study the reactivity of sera from patients with chagasic and non-chagasic myocardiopathies, against surface and secreted proteins from T. cruzi and T. rangeli. Both species are found in the same insect vector, but only T. cruzi is thought to be pathogenic in vertebrates. The ELISA results fell into three patterns: (1) high reactivity values with both T. cruzi and T. rangeli surface and secreted proteins; (2) high values to T. cruzi but low values with T. rangeli; and (3) high values to T. rangeli and low values with T. cruzi. This finding that some chagasic sera react more strongly against T. rangeli than against T. cruzi is intriguing, and warrants further investigation. When chagasic sera were tested on Western blots of total extracts of T. cruzi and T. rangeli, the pattern of reactive bands was similar against both parasites, but no two sera showed an identical pattern. Furthermore, there was no correlation between a particular immunoblotting pattern and either the antibody titer, or the severity of the disease. Several T. cruzi and T. rangeli antigens were recognized by sera from healthy controls as well as from patients with other tropical diseases endemic in Venezuela. Overall, our results suggest that the humoral immune response to trypanosomal antigens is complex, and no single antigen may be the determining factor in the pathogenesis of chagasic myocardiopathy.     

Tetanus immunization and its association to hepatitis B vaccination in patients with chronic renal failure

A defect in the immune response of patients with chronic renal failure leads to low response rates and insufficient antibody concentrations following a number of highly recommended vaccinations. This has been shown before for immunization against hepatitis B and influenza. Few data are available concerning the efficacy of vaccination with tetanus toxoid in these patients. In a prospective, controlled study we vaccinated seronegative patients with chronic renal failure not on dialysis, patients on chronic intermittent hemodialysis, and patients after kidney transplantation with tetanus toxoid. The results were compared with those of a control group consisting of 13 age-matched patients with mild essential hypertension and normal kidney function. Only 11 of 20 (55%) patients in the chronic renal failure group and 16 of 23 (69%) in the dialysis group had a protective antibody response after triple vaccination. In contrast, all the patients in the control group and six of seven transplant patients seroconverted. The response to tetanus toxoid was highly associated with the response to a previously administered vaccination against hepatitis B. Responders to this vaccination also had a better response rate to tetanus toxoid. The antibody concentrations after vaccination were lower in all patient groups compared with the controls; the lowest titers were found in the transplant patients. Therefore, renal patients will need revaccination much earlier, and tetanus toxoid antibody levels should be checked if a patient is injured and potentially requires vaccination.     

Promotion of ulcerative duodenitis in young ferrets by oral immunization with Helicobacter mustelae and muramyl dipeptide

BACKGROUND: The purpose of this study was to determine whether oral immunization of ferret kits with a whole-cell sonicate of Helicobacter mustelae lysate (Hml) and the adjuvant muramyl dipeptide (MDP) would reduce the incidence of natural colonization with H. mustelae and the extent of Helicobacter-associated gastritis by enhancing the host mucosal immune response. MATERIALS AND METHODS: Between the ages of 4 and 11 weeks, 44 ferret kits were gavaged with Hml and various doses of MDP. The extent of gastritis and duodenitis and the immune response to H. mustelae were evaluated. RESULTS: All kits became colonized naturally with H. mustelae and the majority developed mild to severe gastritis and duodenitis. Kits that received Hml with MDP developed significantly greater inflammation of the gastric antrum and duodenum, as compared to kits vaccinated with Hml alone. Vaccination with Hml and 50 micrograms of MDP was associated with severe lesions in the proximal duodenum characterized by accumulation of mononuclear inflammatory cells, mucosal erosion, and ulceration. Although serum antibody specific for H. mustelae in 4-week-old kits was approximately 50% of adult levels, a finding attributable to passively acquired maternal antibody, both systemic and mucosal antibody levels became depressed over time despite oral vaccination. The humoral immune response was sufficiently low to prevent detection of any significant dose effect of MDP on antibody levels among experimental groups. CONCLUSIONS: Oral vaccination of young ferrets with Hml and 50 micrograms MDP increased the risk of Helicobacter-associated mucosal ulceration in the proximal duodenum, which was associated with low humoral (but significant cell-mediated) immune responses to H. mustelae. In retrospect, the frequency of vaccination may have suppressed the systemic humoral immune response, thereby promoting mucosal damage by H. mustelae. The 50-microgram dose of MDP enhanced the cell-mediated immune response, which indirectly contributed to development of severe lesions. The increased frequency of mucosal damage associated with this vaccination regimen enhances the value of the ferret model for studying duodenal ulceration secondary to Helicobacter infection.     

Enhanced jejunal production of antibodies to Klebsiella and other Enterobacteria in patients with ankylosing spondylitis and rheumatoid arthritis

OBJECTIVE: To measure gut immunity directly in jejunal fluid in patients with ankylosing spondylitis (AS) and rheumatoid arthritis (RA). METHODS: Antibodies against three different Enterobacterias were measured in jejunal perfusion fluids (collected by a double balloon perfusion device) of 19 patients with AS, 14 patients with RA, and 22 healthy controls using enzyme linked immunosorbent assay. RESULTS: The AS patients had significantly increased jejunal fluid concentrations of IgM, IgG, and IgA class antibodies against Klebsiella pneumoniae, and IgM and IgA class antibodies against Escherichia coli and Proteus mirabilis compared with healthy controls. When compared with the patients with RA, the AS patients had higher concentrations of IgA and IgG class antibodies only against K pneumoniae. The RA patients had higher IgM class antibody concentrations against all three studied Enterobacterias, when compared with the healthy controls, suggesting an enhanced mucosal immune response in these patients. A three month treatment with sulphasalazine did not decrease enterobacterial antibody concentrations in the 10 patients with AS. CONCLUSION: There is strong direct evidence for an abnormal mucosal humoral immune response particularly to K pneumoniae in patients with AS.     

Spiral CT with ionic and nonionic contrast material: evaluation of patient motion and scan quality

STUDY OBJECTIVES: To determine if subcutaneous administration of influenza vaccine is as immunogenic as the intramuscular route, and to evaluate the frequency of local adverse events associated with both routes in elderly anticoagulated men. DESIGN: Single-blind, prospective study of consecutively enrolled subjects. SETTING: Ambulatory clinic at a university-affiliated Veterans Affairs medical center. PATIENTS: Twenty-six men age 60 years or older, receiving therapeutic dosages of warfarin. INTERVENTIONS: Subjects were randomized to receive either intramuscular or subcutaneous injection of a standard trivalent influenza vaccine. MEASUREMENTS AND MAIN RESULTS: Serum antibody titers to the vaccine's components were measured at baseline, and 6 weeks and 4 months after vaccination. Both routes of administration induced comparable serum antibody titers. There were no differences in adverse events at administration sites between routes of administration. CONCLUSIONS: Elderly individuals are able to mount an immune response to influenza vaccine and produce antibody concentrations deemed protective. The routes of administration are similarly effective at inducing an immune response. The intramuscular route in anticoagulated elderly men does not commonly result in local bleeding complications.     

Immunogenicity and protective role of three formulations of oral cholera vaccine

Three formulations of oral cholera vaccine were compared with respect to their immunogenicity and protective ability in a rat ileal loop model. Eight-week-old Wistar rats were divided into five groups. The first group received orally vaccine A consisting of liposome-associated V. cholera lipopolysaccharide, fimbriae and procholeragenoid, whereas the rats of groups 2 and 3 received orally vaccines B and C consisting of heatkilled fimbriated and non-fimbriated whole cell V. cholerae, respectively. Rats of groups 4 and 5 were controls that received orally liposomes alone and normal saline solution, respectively. It was found that vaccine A elicited stronger immune responses to all three V. cholerae antigens. The antibody responses were detected in both serum and intestinal lavage samples. Vaccine B elicited only modest serum and intestinal responses to V. cholerae fimbriae (anti-F). No detectable immune response was found in rats of group 3 immunized with vaccine C. Rats immunized with vaccines A and B had a similar order of magnitude of numbers of vibrios adhered to their intestinal mucosa. These numbers were less than those associated with the intestinal tissues of control rats of groups 4 and 5 by about two orders of magnitude. Although without any detectable immune response, rats of group 3 that were immunized with vaccine C showed some reduction in numbers of vibrios associated with their intestinal mucosa. The numbers of vibrios recovered from the intestinal segments of rats of all treatment groups were in the order group 1 = 2 < 4 = 5. Electron micrography also revealed patches of vibrio colonization on the mucosa of rats of groups 3, 4 and 5. These features were not found in the groups vaccinated with vaccines A and B. The inhibition of vibrio colonization afforded by the vaccines was biotype- and serotype-non-specific. The results suggest that the heat-killed whole cell fimbriated V. cholerae may be an alternative vaccine preparation to the liposome-associated refined antigen vaccine at a lower cost.     

Effect of prednisone on response to influenza virus vaccine in asthmatic children

OBJECTIVE: To evaluate the immunogenicity of the influenza virus vaccine in children receiving short-course (a burst) prednisone therapy for acute asthmatic exacerbations. DESIGN: Prospective cohort study. SETTING: Outpatient pediatric clinic of a military medical center. PATIENTS: Children aged 6 months to 18 years requiring the 1996 influenza virus vaccine were eligible for the study. A total of 58 children were enrolled initially. The control group included 37 asthmatic children requiring less than 900 microg/d of inhaled prednisone and their siblings. The prednisone group included 21 children vaccinated at the beginning of a course of prednisone prescribed to treat an asthma exacerbation. Thirty-one control subjects (84%) and 19 patients in the prednisone group (90%) completed the study. Dropout was due to failure to come in for the postvaccination serum sampling. INTERVENTIONS: All study patients underwent immunization with the 1996-1997 trivalent subvirion influenza virus vaccine (FluShield; Wyeth Laboratories Inc, Marietta, Pa) containing 15-microg hemagglutinin antigens each of A/Texas/36/91 (H1N1) (A/H1), A/Wuhan/359/95 (H3N2)(A/H3), and B/Beijing/184/93 (B). The prednisone cohort received a burst of oral prednisone therapy (2 mg/kg per day for 5 days). MAIN OUTCOME MEASURES: To assess the immunogenicity of the vaccine between both groups, at least a 4-fold rise in titer and end titers of at least 1:40 to each of the 3 antigens were compared. Mean changes in geometric titers to the 3 antigens were also compared. RESULTS: Proportion of patients in each group with at least a 4-fold rise in titer to each of the influenza antigens was as follows: for A/H3N3 antigen, 15 patients (79%) in the prednisone group vs 22 controls (71%) (P = .74); for A/ H1N1 antigen, 16 patients in the prednisone group (84%) vs 20 controls (64%) (P = .20); and for B antigen, 7 patients in the prednisone group (37%) vs 8 controls (26%) (P = .53). Proportion of patients in each group with an end titer of at least 1:40 to each of the antigens was as follows: for A/ H3N2 antigen, 18 patients in the prednisone group (95%) vs 28 controls (90%) (P = .69); for A/H1N1 antigen, 17 patients in the prednisone group (89%) vs 26 controls (84%) (P = .99); and for B antigen, 7 patients in the prednisone group (37%) vs 13 controls (42%) (P = .99). There were also no significant differences between groups in the mean changes in geometric titers to any of the 3 antigens. CONCLUSIONS: Prednisone bursts did not diminish the response of asthmatic children to the 1996 influenza virus vaccine, compared with controls. Children can be effectively vaccinated against influenza virus while they are receiving prednisone therapy bursts for asthmatic exacerbations.     

Antibody response to whole-virus and split-virus influenza vaccines in successful ageing

The antibody response to influenza vaccination has been variably reported to be decreased in elderly individuals. To determine the effect of ageing alone on this antibody response, a group of carefully-screened healthy elderly subjects were compared with young adult controls. Antibody titres for several strains of influenza were measured before and after vaccination with whole-virus (WVV) and split-virus influenza vaccines (SVV) in two successive years. In general, the antibody response to WVV was greater than the response to SVV. Both groups showed a similar response to the H3N2 strain but the elderly group showed a lower response to the H1N1 and B strains of virus contained in the vaccine. Antibodies to older strains of influenza A but not B were stimulated by vaccination with SVV. In the elderly group, the response to older viral strains was relatively increased compared with newer strains. In contrast, the young control group had better antibody responses to the newer than to the older strains of influenza tested. Reductions in the antibody response to influenza vaccination may, therefore, be related to the phenomenon of original antigenic sin and the cohort effect of exposure to H1N1 during childhood in the elderly group studied. The increased immunogenicity of WVV must be considered in light of the current wide use of SVV in the elderly.