Presence of high levels of non-degraded gliadin in breast milk from healthy mothers

BACKGROUND: Secretion of dietary antigens into breast milk has been extensively documented. The presence of these antigens is of relevance because they could be involved in the modulation of the immune response in neonates. The objective of this study is to determine the gliadin concentration in milk, colostrum, and serum samples from healthy lactating mothers on a normal diet. Gliadin levels in milk samples from a group of six mothers after a brief period of gluten restriction were also determined. The molecular weight of secreted gliadins was also analysed. METHODS: Gliadin concentration was determined with a highly sensitive competitive enzyme-linked immunosorbent assay, modified so as to eliminate anti-gliadin antibody interference. The level of gliadin/IgA anti-gliadin immune complexes in milk, colostrum, and serum samples was determined. RESULTS: Gliadin was detected in all 49 milk samples. Its concentration varied between 5 and 1200 ng/ml (mean, 178 ng/ml). In colostrum (n = 14) gliadin levels were higher (range, 28-9000 ng/ml; mean, 883 ng/ml), not being detectable in one case. Gliadin was detectable in 14 of 31 serum samples, in which levels were lower than in milk and colostrum samples (mean, 41 ng/ml). Neither a correlation between gliadin levels in milk, colostrum, and serum samples from the same subject nor a relation between gluten intake and gliadin concentration in milk samples from six subjects under a 3-day gluten-free diet could be found. Higher levels of immune complexes were observed in colostrum samples than in milk and serum samples. No correlation was detected between gliadin concentration and the level of immune complexes. The analysis of milk and colostrum samples by immunoblotting showed bands of immunoreactive gliadin presenting Mr similar to those of native proteins from wheat extracts. CONCLUSIONS: Very high levels of gliadin were detected in milk samples from healthy mothers on an unrestricted diet. Gliadin levels were higher than those reported for dietary antigens in other studies. Breast milk contained non-degraded gliadins and gliadin/anti-gliadin IgA immune complexes.     

The importance of measuring plasma carcinoembryonic antigen in small-cell anaplastic carcinoma

The clinical value of the serum biomarker carcinoembryonic antigen (CEA) was evaluated prospectively in 118 patients with small cell lung cancer (SCLC) entered chemotherapy protocol between 1986 and 1992. Five quantitative categories were determined: less than 2.5 ng/ml and 2.6-5.0 ng/ml (the standard normal), 5.1-20.0 ng/ml, 20.1-100 ng/ml and greater than 100 ng/ml. 70% of patients had levels less than 5 ng/ml and only 19% had levels greater than 20 ng/ml. There was no clearcut relationship of plasma CEA level to stage of disease, in which 61% of patients with extensive disease (59 patients) had levels less than 5 ng/ml and 22% of patients with limited disease (59 patients) had levels greater than 5 ng/ml. There was a modest relationship of CEA levels to presence of metastases, in that 50% of patients with metastases had levels greater than 20 ng/ml. The average survival for the pathologic and normal category was almost similar, ranging from 13.27 to 16.81 months. The correlation between disease extent and survival was more sensitive for lactate dehydrogenase (LDH) than for CEA. So CEA as a tumor marker for SCLC must be applied in conjunction with other biomarkers, particularly LDH and neuron specific enolase (NSE) and is meaningful in only a small proportion of patients.     

Plasma carcinoembryonic antigen in an Australian hospital population

Plasma carcinoembryonic antigen (CEA) levels have been determined by the zirconyl phosphate gel (Z-gel) method, using materials provided by Hoffman-LaRoche Inc., on 512 samples from 425 hospital patients, and on single samples from 124 normal controls (98 blood donors and 26 healthy staff members). Of the controls, 98% had CEA levels less than 5 ng/ml. Forty-six hospital patients had CEA levels above 20 ng/ml; 45 (98%) had known present or past cancer. Nineteen patients had levels between 10 and 20 ng/ml; 11 (58%) had present or past cancer. Sixty-seven patients had levels between 5 and 10 ng/ml, and most of these had non-malignant diseases; only 34% had present or past cancer. Cigarette smoking was associated with elevated CEA levels among patients with non-neoplastic diseases, notably those with cirrhosis of the liver and chronic renal disease. There was a gradation of increasing specificity for cancer with increasing levels of CEA from 5 to over 20 ng/ml; but, on the other hand, higher levels were associated with more disseminated cancer, which would be less amenable to cure.     

Prognostic use of preoperative and immediate postoperative carcinoembryonic antigen determinations in colonic cancer

Preoperative and postoperative carcinoembryonic antigen (CEA) concentrations are useful in predicting the likelihood of recurrence in patients undergoing curative operations for cancer of the colon. The incidence of recurrence was studied in three groups of patients followed for 6 to 18 months after such an operation: 36 patients (group 1) had preoperative and postoperative plasma CEA concentrations less than 2.5 ng/ml; 11 patients (group 2) had a preoperative CEA value above but a postoperative value below 2.5 ng/ml; and 11 patients (group 3) had preoperative and postoperative concentrations greater than 2.5 ng/ml. Cumulative rates of recurrence at 6, 12 and 18 months after operation were as follows: 0, 3 and 17% in group 1; 0, 9 and 21% in group 2; and 27, 79 and 79% in group 3. Statistically there was no difference in the recurrence rate between groups 1 and 2, but the rate was significantly lower in group 2 compared with group 3. The data show that patients in whom the immediate postoperative CEA concentration returns to normal have a much lower incidence of recurrent cancer of the colon than patients whose CEA concentration remains elevated.     

Video-imaging and treatment presentation: medico-legal implications and patient perception

Peripheral blood leukocyte alkaline phosphatase (LAP) scores and CA15-3, CA125, and CEA levels in plasma were measured in 57 patients with metastatic breast, ovarian, and colorectal cancer, respectively, and in 79 patients with the same types of nonmetastatic cancer. The mean LAP scores of the metastatic cancer patients (261, 272 and 275 for breast, ovary and colon, respectively) were significantly higher than those of the nonmetastatic cancer group (70, 68 and 57, respectively). There was no overlap between the 95% confidence intervals of the two groups (i.e., metastatic versus nonmetastatic), and no patient known to be metastatic had a LAP score within the normal range. The mean levels of other markers in the metastatic patients (CA15-3, 63.4 mu/ml; CA125, 104.8 mu/ml; and CEA, 51.8 ng/ml for metastatic breast, ovarian, and colon cancer, respectively) were also higher than in the nonmetastatic patients (CA15-3, 24 mu/ml; CA125, 25.3 mu/ml; and CEA, 5.8 ng/ml for nonmetastatic breast, ovarian, and colon cancer, respectively). However, the 95% confidence intervals of the nonmetastatic and the metastatic patients overlapped so that there were false-negatives and/or false-positives when the other markers were used. We therefore conclude that the addition of the LAP score to conventional cancer markers could be helpful for the diagnosis of recurrence and follow-up of cancer patients and suggest that our results be confirmed by further studies on a larger series of patients.     

Birthmarks to worry about. Cutaneous markers of dysraphism

CYFRA 21-1 is a fragment of cytokeratin 19 (CK 19). Four patients with large intrahepatic (or peripheral) cholangiocarcinoma (CC) and high serum levels of CYFRA 21-1 (normal, < or = 2 ng/ml) are reported. CYFRA 21-1 levels exceeded 9 ng/ml in all 4 patients. Carcinoembryonic antigen (CEA), was high in 1 (CEA; normal range, < or = 5.0 ng/ml) and carbohydrate antigen 19-9 (CA 19-9) was high in 3 (CA19-9; normal range, < or = 36 U/ml). We also measured serum levels of CYFRA 21-1 in 13 patients with hepatocellular carcinoma (HCC) more than 5 cm in diameter. Levels of CYFRA 21-1 exceeded 2 ng/ml in 9 of the HCC patients and were higher than 9 ng/ml in 2 of the HCC patients. Levels of alpha fetoprotein (AFP) and/or protein induced by vitamin K absence or antagonist II (PIVKA II) were elevated in all HCC patients (AFP, PIVKA II, respectively; normal range, < or = 10.0 ng/ml and < or = 0.1 AU/ml) CYFRA 21-1 levels were measured twice or three times during the clinical course in 2 CC patients and in 6 HCC patients, and increased gradually with tumor growth in the 2 CC patients and in 3 of the 6 HCC patients. Marked increases in serum CYFRA 21-1 levels in patients with large liver cancers, particularly in those with normal levels of AFP and PIVKA II, would suggest the existence of intrahepatic CC rather than HCC.     

The evaluation of carcinoembryonic antigen determination in the pericardial fluid in the diagnosis of the cause of pericarditis

Pericardial fluid CEA level was measured with radioimmunoassay in 19 patients with large pericardial effusion of unknown origin. In 11 patients malignancy was diagnosed. In all of these patients pericardial fluid CEA levels were above 7 ng/ml (mean value 52.6 +/- 42.6 ng/ml). In 8 patients the etiology of pericarditis was non-malignant. In all of them pericardial fluid CEA levels were below 7 ng/ml (mean value 2.2 +/- 1.6 ng/ml). In 9 patients with malignant pericarditis serum CEA levels were also determined: they were found to be lower than pericardial fluid CEA values in 6 patients. It was concluded that pericardial fluid CEA elevation is a reliable criteria of neoplastic pericardial involvement.     

Dystrophic calcification of silicone scleral buckling implant materials

The local antibody response to the outer membrane protein, P6, of nontypable H. influenzae was measured in middle ear fluids of 30 children during 46 episodes of otitis media, and in nasopharyngeal secretions from 7 children evaluated on 18 occasions. Immunoglobulin G antibody to P6 was detected in 92% of middle ear fluid compared to 70% for IgM, 78% for IgA, and 45% for secretory IgA. Antibody levels ranged from a high of 249 ng/ml for IgG to a low of 11 ng/ml for IgM. Concentrations of P6 specific IgG in the middle ear fluid was directly related to the concentration in the serum, r = 0.89, p < 0.001, and inversely related to the number of bacteria present, r = -0.62, p < 0.05. In contrast, IgA and secretory IgA antibodies to P6 were common (96% and 95%, respectively) and in relatively high concentrations (33 ng/ml and 29 ng/ml, respectively) in nasopharyngeal secretions. There was no relationship between nasopharyngeal and serum levels of antibodies. These data suggest that antibody to P6 nontypable H. influenzae is common, diffuses into the middle ear spaces passively from the serum during otitis media, and is manufactured locally in the nasopharynx in response to colonization.     

Petrous meningioma en plaque presenting as a right middle ear tumor

Levels of carcinoembryonic antigen (CEA) and glucose phosphate isomerase (GPI) have been compared in the circulating blood of hamsters bearing intra-muscular grafts of GW-39 human colonic tumour. CEA in the sera of GW-39 tumour-bearing hamsters ranged from 2-6 to 8-4 ng/ml (mean = 4-5 +/- 1-7 ng/ml). GPI in the sera of normal hamsters ranged from 332 to 749 iu/1 (mean = 602 +/- 110 iu/1) while those with 14-week-old intra-muscular grafts of a hamster amelanotic melanoma, (A.Mel.3), or GW-39 human colonic carcinoma had a range of 664 to 1267 iu/1 (mean = 1024 +/- 220 iu/1) and 1430 to 4719 iu/1 (mean = 2065 +/- 601 iu/1) respectively. Thus, the ratio of enzyme activity in GW-39, A.Mel.3, and normal hamsters was 3-4:1-7:1, indicating a significant elevation (P less than 0-01) in animals bearing a human colon carcinoma or a hamster melanoma, with particularly high values obtained in hamsters with GW-39. Sequential determinations of CEA and GPI in a group of hamsters transplanted intra-muscularly with GW-39 tumours revealed that both markers increased proportionately with duration of tumour growth, suggesting that both serum CEA and GPI may be used as measures of tumour growth. The concentration of GPI in GW-39 human colonic carcinoma xenografts was also significantly higher than that measured in normal human colon, primary human colonic cancer, or normal hamster tissues. These results support the view that GPI, in addition to CEA, is a quantitatively increased marker in this tumour model, and is liberated into the circulation in proportion to the increase in tumour mass.     

ELISA for complexes between urokinase-type plasminogen activator and its receptor in lung cancer tissue extracts

A sandwich-type ELISA has been developed for the assessment of complexes between urokinase-type plasminogen activator (uPA) and its receptor (uPAR) in extracts of squamous cell lung carcinomas. The assay is based on a combination of rabbit polyclonal anti-uPA antibodies and a biotinylated mouse anti-uPAR monoclonal antibody (MAb). The detection limit of the assay is approximately 0.5 fmol/ml. A linear dose-response is obtained with up to 40 fmol/ml of uPA:uPAR complexes, while uPA and uPAR separately do not cause any response in the ELISA. A buffer which has been used previously for optimal extraction of uPAR yields the highest amounts of uPA:uPAR complexes. Absorption of tumor extracts with anti-uPA or anti-uPAR MAbs results in a complete disappearance of the ELISA signal, demonstrating the specificity of the ELISA. The recovery of chemically cross-linked uPA:uPAR complexes added to tumor extracts varies between 80% and 105%. The intra- and inter-assay variation coefficients are 5.3% and 9.8%, respectively. Furthermore, a peptide antagonist for uPAR was employed to evaluate de novo uPA:uPAR complex formation during tumor tissue extraction and the immunoassay procedure. Our results strongly indicate that de novo complex formation is a major factor to consider and that complexes analyzed in the presence of this antagonist represent original uPA:uPAR complexes present prior to tumor tissue processing. The present ELISA appears suitable for studying the potential prognostic impact of uPA:uPAR complexes in lung tumor tissue as well as other types of cancer.     

Clinical evaluation of chemiluminescence immunoassay PSA (ACS-PSA) for detection of prostate cancer

Serum prostate specific antigen (PSA) levels were measured using an ACS-PSA kit in 147 systematic biopsy cases (61 with prostate cancer (PC)) and 96 transurethral resection of prostate (TUR-P) cases (2 with PC). In the 147 biopsy cases, the sensitivity for PSA using 3.0 and 10.0 ng/ml as cut-off values was 91.8 and 90.2%, while the specificity was 9.30 and 30.2%, respectively. The sensitivity for PSAD (A) (calculated by transabdominal ultrasound) using 0.25 and 0.5 ng/ml/cm3 as cut-off values was 91.8 and 90.2%, while the specificity was 22.1 and 50.0%, respectively. These data indicated that PSAD (A) provided better information for detecting PC than PSA alone. No statistical difference was found between PSAD (A) and PSAD (R) (calculated by transrectal ultrasound) in the utility of detecting PC. PSA below 15.0 ng/ml was seen in sixteen patients with PC. Five of these sixteen patients had a PSA level of < 3.0, and they underwent prostate biopsy based on the abnormality by digital rectal examination (DRE). The other eleven patients had PSAD (A) level of > 0.3 ng/ml/cm3. In all 243 cases, PC was not found in the 49 patients (PSA < 3.0 ng/ml) or 91 patients (PSAD (A) < 0.25 ng/ml/cm3) who had no abnormal findings by DRE and transabdominal ultrasonography. These results suggested a criterion in the use of the ACS-PSA kit for the indication of prostate biopsy and TUR-P.     

Demonstration of a 65 kDa tumor-specific phosphoprotein in urine and serum of rats with N-methyl-N-nitrosourea-induced mammary adenocarcinomas

Polyclonal antibodies against a 65 kDa tumor-associated phosphoprotein (p65) were used to develop an ELISA to analyze the presence of p65 in urine and serum of rats bearing N-methyl-N-nitrosourea-induced mammary gland adenocarcinomas. Highly purified rat p65 was added to normal urine and serum to establish a quantitative standard curve with the average correlation coefficient being 0.98 and 0.99 respectively. All samples of urine and serum obtained from different carcinoma-bearing rats showed p65 concentrations above the normal levels found in the control urine and sera. The correlation coefficient between tumor burden and p65 concentration in urine and serum was 0.65 and 0.77 respectively. The average levels of p65 in normal urine and normal serum were 37.0 +/- 32.0 and 48.0 +/- 38.0 ng/ml respectively. In the case of urine obtained from rats bearing mammary adenocarcinomas, the mean p65 level was 119.0 +/- 35.9 ng/ml and their serum level was 225.4 +/- 67.5 ng/ml. Sensitivity, specificity and predictive value for serum and urine marker elevation were 78.5, 70.0 and 78.5% respectively. Following in vitro phosphorylation of concentrated urinary proteins, isoelectrofocusing, SDS-PAGE and autoradiography, a phosphorylated form of the 65 kDa protein with a pI of 5.8 was identified in the urine of tumor-bearing rats. This phosphoprotein bound to an antiphosphotyrosine monoclonal antibody and an anti-p65 polyclonal as determined by Western blot analysis. Using the anti-p65 antibodies in an immunoprecipitation procedure, the main radio- and immunoactive band of 65 kDa and two lower mol. wt bands of 50 and 41 kDa, apparently representing degradation products of p65, were identified after in vitro and in vivo phosphorylation of urinary proteins obtained from mammary carcinoma-bearing rats.     

S-100 protein concentration in the cerebrospinal fluid of patients with Creutzfeldt-Jakob disease

We evaluated S-100 levels in paired cerebrospinal fluid (CSF) and serum samples in a group of 135 patients referred to the German Creutzfeldt-Jakob disease (CJD) surveillance unit from June 1993 to May 1995. The patients were seen in a prospective case control study. The diagnosis of probable CJD during life was made in any patient presenting with rapidly progressive dementia of less than 2 years' duration, typical periodic sharp wave complexes (PSWCs) in the EEG and at least two of the following findings: myoclonus, visual/or cerebellar symptoms, pyramidal and/or extrapyramidal signs and/or akinetic mutism. Patients presenting with the above clinical signs and symptoms but without PSWCs were classified as possible, while those with a dementia of a duration exceeding 2 years and without PSWCs were classified as other. S-100 was determined in paired CSF and serum samples by a commercially available enzyme-linked immunosorbent assay. In a group of 76 patients with definite and probable CJD, S-100 concentration (median 25 ng/ml, range 2-117) in CSF was significantly higher (P < 0.0001) than in 32 patients diagnosed as other (median 4 ng/ml, range 1-19). Serum levels of S-100 were below 0.5 ng/ml in all groups. At a cut-off of 8 ng/ml an optimum sensitivity of 84.2% with a specificity of 90.6% for the diagnosis of CJD by the determination of S-100 in CSF is obtained. S-100 levels exceeding 8 ng/ml in CSF support the diagnosis of CJD in any patient presenting with rapidly progressive dementia.     

Carcinoembryonic antigen (CEA) assays in obstructive colorectal cancer

Four of 40 patients with resectable colon or rectal cancer had tumors causing acute large bowel obstruction with colonic dilatation; all 4 patients had preoperative CEA titers above 10 ng/ml with a mean of 28 ng/ml. Thirty-six cancer patients without acute colon obstruction had a mean CEA titer of 4.5 ng/ml; only 6 of 36 patients had circulating CEA titers 10 ng/ml or greater. This suggested that pre-treatment CEA titers in patients with obstructing cancer are unusually high. Multiple CEA assays were performed on two of the 4 patients with colonic obstruction before and after bowel decompressive procedures and prior to their definitive treatment. Relief of obstruction alone produces marked reduction in circulating CEA; this suggested that not only the extent of disease but also the pathophysiological changes associated with obstruction influenced circulating CEA levels.     

N-acetyl-L-cysteine protects endothelial cells but not L929 tumor cells from tumor necrosis factor-alpha-mediated cytotoxicity

The effect of N-acetyl-L-cysteine on the cytotoxicity of tumor necrosis factor-alpha was investigated in cultured bovine pulmonary artery endothelial cells and L929 mouse tumor cells. In endothelial cells, a 72-h incubation with tumor necrosis factor-alpha (100 ng/ml) reduced the number of viable cells to 27% of control. Simultaneous incubation with N-acetyl-L-cysteine (0.5-5 mmol/l) protected endothelial cells from tumor necrosis factor-alpha-mediated cytotoxicity and increased viability in a concentration-dependent fashion to 69% of control. Under the same conditions, a 72-h incubation with tumor necrosis factor-alpha (100 ng/ml) reduced the number of viable L929 tumor cells to 31% of control. However, this cytotoxic response remained unaltered in the presence of N-acetyl-L-cysteine (0.5-5 mmol/l). Similar results were obtained when using a lower concentration of tumor necrosis factor-alpha (50 ng/ml). These findings demonstrate protection from tumor necrosis factor-alpha-mediated toxicity by N-acetyl-L-cysteine in endothelial cells but not in a tumor cell line. It is concluded that N-acetyl-L-cysteine might serve as a therapeutic agent to limit the vascular toxicity of tumor necrosis factor-alpha without affecting its antineoplastic activity.     

Dose escalation trial of indium-111-labeled anti-carcinoembryonic antigen chimeric monoclonal antibody (chimeric T84.66) in presurgical colorectal cancer patients

Chimeric T84.66 (cT84.66) is a high-affinity (1.16x10(11) M(-1)) IgG1 monoclonal antibody against carcinoembryonic antigen (CEA). The purpose of this pilot trial was to evaluate the tumor-targeting properties, biodistribution, pharmacokinetics and immunogenicity of 111In-labeled cT84.66 as a function of administered antibody protein dose. METHODS: Patients with CEA-producing colorectal cancers with localized disease or limited metastatic disease who were scheduled to undergo definitive surgical resection were each administered a single intravenous dose of 5 mg of isothiocyanatobenzyl diethylenetriaminepentaacetic acid-cT84.66, labeled with 5 mCi of 111In. Before receiving the radiolabeled antibody, patients received unlabeled diethylenetriaminepentaacetic acid-cT84.66. The amount of unlabeled antibody was 0, 20 or 100 mg, with five patients at each level. Serial blood samples, 24-hr urine collections and nuclear images were collected until 7 days postinfusion. Human antichimeric antibody response was assessed up to 6 mo postinfusion. RESULTS: Imaging of at least one known tumor site was performed in all 15 patients. Fifty-two lesions were analyzed, with an imaging sensitivity rate of 50.0% and a positive predictive value of 76.9%. The antibody detected tumors that were not detected by conventional means in three patients, resulting in a modification of surgical management. Interpatient variations in serum clearance rates were observed and were secondary to differences in clearance and metabolic rates of antibody and antibody:antigen complexes by the liver. Antibody uptake in primary tumors, metastatic sites and regional metastatic lymph nodes ranged from 0.4% to 134% injected dose/kg, resulting in estimated 90Y-cT84.66 radiation doses ranging from 0.3 to 193 cGy/mCi. Thirteen patients were evaluated 1-6 mo after infusion for human antichimeric antibody, and none developed a response. No major differences in tumor imaging, tumor uptake, pharmacokinetics or organ biodistribution were observed with increasing protein doses, although a trend toward increasing blood uptake and decreasing liver uptake was observed with increasing protein dose. CONCLUSION: Chimeric T84.66 demonstrated tumor targeting comparable to other radiolabeled intact anti-CEA monoclonal antibodies. Its immunogenicity after single administration was lower than murine monoclonal antibodies. These properties make 111In-cT84.66, or a lower molecular weight derivative, attractive for further evaluation as an imaging agent. Yttrium-90 dosimetry estimates predict potentially cytotoxic radiation doses to select tumor sites, which makes 90Y-cT84.66 also appropriate for further evaluation in Phase I radioimmunotherapy trials. Although clinically important changes in biodistribution, pharmacokinetics and tumor targeting with increasing protein doses of 111In-cT84.66 were not demonstrated, the results do suggest that antibody clearance from the blood is driven by hepatic uptake and metabolism, with more rapid blood clearance seen in patients with liver metastases. These patients with rapid clearance and potentially unfavorable biodistribution for imaging and therapy may, therefore, be a more appropriate subset in which to evaluate the role of administering higher protein doses. This underscores the need to further identify, characterize and understand those factors that influence the biodistribution and clearance of radiolabeled anti-CEA antibodies, to allow for better selection of patients for therapy and rational planning of radioimmunotherapy.     

Prejunctional effects of cromakalim, nicorandil and pinacidil on noradrenergic transmission in rat isolated mesenteric artery

Quil A used with Boophilus microplus gut membrane antigen (GM) had a significant effect on antibody levels induced in sheep (P < 0.05) since GM alone did not induce a significant level of antibodies. Injection of a vaccine containing GM and Quil A, either subcutaneously or intramuscularly, induced similar levels of antibodies in sheep. However, Quil A injected subcutaneously induced acute inflammatory reaction. The amount of Quil A for use with GM was determined to be 1000 micrograms/ml. Immunostimulating complexes (ISCOMs) incorporating detergent-solubilized membrane midgut antigens (TX-GM) failed to induce an immune response in cattle without the addition of Quil A. The addition of Quil A to the ISCOMs containing TX-GM did not stimulate antibody responses greater than those stimulated by TX-GM plus Quil A, and protection in vaccinated cattle was 86% and 74%, respectively.     

Induction of protective host immunity to carcinoembryonic antigen (CEA), a self-antigen in CEA transgenic mice, by immunizing with a recombinant vaccinia-CEA virus

Human carcinoembryonic antigen (CEA) is a well-characterized oncofetal glycoprotein whose overexpression by human carcinomas has been a target for cancer immunotherapy. Transgenic mice that express CEA as a self-antigen with a tissue distribution similar to that of humans have been developed. This study investigates: (a) the responsiveness of the CEA transgenic (CEA.Tg) mice to endogenous CEA or CEA administered as a whole protein in adjuvant; and (b) whether the presentation of CEA as a recombinant vaccinia virus could generate CEA-specific host immunity. By and large, the CEA.Tg mice were unresponsive to CEA, as shown by the lack of detectable CEA-specific serum antibodies and the inability to prime an in vitro splenic T-cell response to CEA. Furthermore, the administration of whole CEA protein in adjuvant to CEA.Tg mice failed to elicit either anti-CEA IgG titers or CEA-specific T-cell responses. Only weak anti-CEA IgM antibody titers were found in those mice. In contrast, CEA.Tg mice immunized with recombinant vaccinia virus expressing CEA generated relatively strong anti-CEA IgG antibody titers and demonstrated evidence of immunoglobulin class switching. These mice also developed T(H)1-type CEA-specific CD4+ responses and CEA peptide-specific cytotoxicity. The ability to generate CEA-specific host immunity correlated with protection of the CEA.Tg mice against a challenge with CEA-expressing tumor cells. Protection against tumor growth was accomplished with no apparent immune response directed at CEA-positive normal tissue. The results demonstrate the ability to generate an effective antitumor immune response to a tumor self-antigen by immunization with a recombinant vaccinia virus. CEA.Tg mice should be an excellent experimental model to study the effects of more aggressive immunization schemes directed at established tumors with the possible development of accompanying autoimmune responses involving normal tissues.     

Tobacco use and other risk behaviors among adolescents in an STD clinic

OBJECTIVE: To test efficacy of murine monoclonal, rabbit polyclonal recombinant equine or human tumor necrosis factor-alpha (rETNF or rHTNF, respectively) antibodies to inhibit native equine tumor necrosis factor (TNF) activity. ANIMALS: 8 and 18 healthy adult horses for parts 1 and 2 of the study, respectively. PROCEDURES: In part 1, supernates from endotoxin-activated peritoneal macrophages were incubated with various dilutions of each rETNF antibody and subsequently tested for TNF activity. Serum was also obtained from a horse 1 hour after infusion with 20 ng of endotoxin/kg of body weight and was incubated with various dilutions of rabbit polyclonal rHTNF antibody. In part 2, 20 ng of endotoxin/kg was infused in horses during a 30-minute period. Fifteen minutes after the endotoxin infusion was initiated, 1 of 3 preparations was infused: 0.1 mg of rabbit polyclonal (rHTNF antibody/kg, 0.1 mg of human IgG/kg, or 500 ml of 5% dextrose. Clinical and hematologic data were collected for 24 hours. RESULTS: Compared with the monoclonal antibody, the rabbit polyclonal rETNF antibody was more effective in inhibiting TNF activity. The 50% effective doses of the murine monoclonal rETNF, rabbit polyclonal rETNF, and rabbit rHTNF antibodies were 1.8, 0.8, and 0.6 micrograms of antibody/ml, respectively. In part 2, endotoxin infusion resulted in significant alternations in all variables; however, differences among treatment groups were not significant. CONCLUSIONS AND CLINICAL RELEVANCE: Although murine monoclonal and rabbit polyclonal rETNF or rHTNF antibodies are capable of inhibiting native equine TNF activity in vitro, when given after initiation of endotoxemia, administration of 0.1 mg of rabbit polyclonal rHTNF/kg does not alter the response to infusion of endotoxin.