The tissue and cell defense mechanisms of the oral mucosa

The modern concepts of tissue and cell defense mechanisms in oral mucosa are discussed. These mechanisms include (a) physical barriers (of epithelium and lamina propria), (b) non-specific antimicrobial humoral factors, (c) non-specific cellular defense mechanisms, (d) specific immune humoral and cell-mediated defense mechanisms, (c) saliva, containing both non-specific and specific antimicrobial factors. Special reference is given to antigen-presenting dendritic cells and various lymphocyte subpopulations both in epithelium and in lamina propria. The interaction of different cell and tissue defense mechanisms and their regional variations are briefly characterized.     

The development of a finger joint phantom for the optical simulation of early inflammatory rheumatic changes

A series of 5-aminomethinimino-3-methyl-4-isoxazolecarboxylic acid phenylamides 4 has been prepared by condensation of 5-amino-3-methyl-4-isoxazolecarboxylic acid phenylamides 1 with trichloroacetic aldehyde. Alcoholysis of trichloro derivatives 2 gave 5-alkoxymethine derivatives 3 which, on reaction with an appropriate amine, formed the corresponding compounds 4. The compounds obtained were evaluated for their immunological activity. The properties of three compounds, described in this report, permitted inhibition of the immune response in all possible ways: diminishing both types of immune response (4d), humoral immune response (4a), or cellular immune response (4c). Preparation 4d is comparable in its effectiveness to CsA, so it may be potentially used as an agent for prolongation of the function of transplanted organs. Two other compounds may potentially be used in cases where only one type the immune response is required for combating pathogen invasion.     

Analysis of the Drosophila host defense in domino mutant larvae, which are devoid of hemocytes

We have analyzed the Drosophila immune response in domino mutant larvae, which are devoid of blood cells. The domino mutants have a good larval viability, but they die as prepupae. We show that, on immune challenge, induction of the genes encoding antimicrobial peptides in the fat body is not affected significantly in the mutant larvae, indicating that hemocytes are not essential in this process. The hemocoele of domino larvae contains numerous live microorganisms, the presence of which induces a weak antimicrobial response in the fat body. A full response is observed only after septic injury. We propose that the fat body cells are activated both by the presence of microorganisms and by injury and that injury potentiates the effect of microorganisms. Survival experiments after an immune challenge showed that domino mutants devoid of blood cells maintain a wild-type resistance to septic injury. This resistance was also observed in mutant larvae in which the synthesis of antibacterial peptides is impaired (immune deficiency larvae) and in mutants that are deficient for humoral melanization (Black cells larvae). However, if domino was combined with either the immune deficiency or the Black cell mutation, the resistance to septic injury was reduced severely. These results establish the relevance of the three immune reactions: phagocytosis, synthesis of antibacterial peptides, and melanization. By working in synergy, they provide Drosophila a highly effective defense against injury and/or infection.     

Enhanced responses to a DNA vaccine encoding a fusion antigen that is directed to sites of immune induction

Viral infection and vaccination with DNA both induce similar immune responses to encoded antigens that are produced by the host. The availability of antigens in lymphoid organs is important in generating an immune response to viral challenge. Antigen availability may also be important in the response to DNA vaccines, because immune responses are stronger when antigen is secreted from DNA-transfected cells. We directed antigen to lymphoid organs by vaccination with DNA encoding antigen-ligand fusion proteins. The two ligands examined bind to receptors that are present on high endothelial venule cells of lymph nodes or on antigen-presenting cells. Here we show that both the humoral and the cellular immune responses to a model DNA vaccine were enhanced using either antigen-targeting strategy. Moreover, directing antigen to antigen-presenting cells speeded up, and altered the form of, the immune response. Directing antigen to sites of immune-response induction may represent a generic means of tailoring a potent and effective immune response to a DNA vaccine.     

Comparative study of cyclophosphamide, 6-mercaptopurine, azathiopurine and methotrexate. Relative effects on the humoral and the cellular immune response in the mouse

The effects of cyclophosphamide, methotrexate, azathioprine and 6-mercaptopurine on the concomitant development of the humoral and the cellular immune responses of mice to a single antigen, the El4 tumour cell, were investigated. The measurements of cellular and humoral immunity were carried out in the same animal using lymphocyte and antibody mediated lysis of the El4 cell, a measurement system independent of underlying anti-inflammatory effects. A regimen of daily cyclophosphamide had a more pronounced suppressive effect on the humoral response than on the cellular response, in agreement with other investigators. A single low dose of cyclophosphamide stimulated the cellular response and suppressed the humoral response. Single or multiple high doses of cyclophosphamide maximally suppressed both the cellular and humoral response. Azathioprine and 6-mercaptopurine, in contrast to the results of other investigations, caused equivalent inhibition of both the humoral and cellular responses and thus lacked selectivity. Methotrexate also provided equivalent inhibition of both the humoral and cellular responses at all dose levels investigated.     

Humoral and cell-mediated immune responses following lesions of the nucleus basalis magnocellularis in the rat

The present study was undertaken to elucidate whether electrolytic lesions of nucleus basalis magnocellularis--NBM (an animal model of Alzheimer's disease--AD) may influence humoral and cellular immune responses in adult male Wistar rats. For this purpose intact control (IC), sham-operated (SO) and NBM-lesioned rats were divided into two main groups: (1) rats immunized with sheep red blood cells (SRBC) for plaque-forming cell (PFC) response and anti-SRBC agglutinins, and (2) rats immunized with bovine serum albumin in complete Freund's adjuvant (BSA-CFA) for anti-BSA antibody production, Arthus and delayed hypersensitivity skin reaction to BSA. PFC responses and anti-SRBC agglutinins as well as diameter and expression of edema/induration of Arthus/delayed skin reaction and titer of anti-BSA antibody were significantly lower in NBM lesioned rats (compared to IC and SO). The results showed that in NBM-lesioned rats both the humoral and cellular immune responses were suppressed.     

Endogenous immune response to glutamic acid decarboxylase (GAD67) in NOD mice is modulated by adjuvant immunotherapy

We have shown that immunization of non-obese diabetic (NOD) mice with adjuvants (CFA or BCG) prevents the onset of diabetes by induction of regulatory cells. Since autoimmune responses to glutamic acid decarboxylase (GAD) are up-regulated in insulin-dependent diabetes mellitus (IDDM), in this study GAD67-specific antibody, T cell proliferation and lymphokine production patterns were analysed in the adjuvant-treated mice to characterize the regulatory mechanisms underlying the protection. We used both spontaneous diabetes and syngeneic islet transplantation models in NOD mice. Protection against spontaneous diabetes and prevention of syngeneic islet graft rejection by CFA or BCG treatment was found to be accompanied by the production of long lasting and high titre anti-GAD67 antibody of IgG1 isotype in the sera. Upon in vitro stimulation with GAD67, draining lymph node and spleen cells from CFA-immunized NOD mice or syngeneic islet-grafted and BCG-protected NOD mice produced much more IL-4, whereas there was no significant change in IFN-gamma production. The strong early T cell proliferative response to GAD67 in CFA or BCG-immunized NOD mice was followed by a low or unresponsiveness state. Taken together, these results suggest a shift in Th1/Th2 balance in the GAD67-specific endogenous immune response to a change in Th2 levels after adjuvant treatment. We postulate that the protective effect of CFA or BCG is due to the diversion of GAD-specific endogenous cellular immune response to a non-pathogenic humoral response.     

Isolation of a bioactive Ca(2+)-mobilizing complex lipid from bovine vitreous body

We have been undertaking the gene therapy for a 6 year-old boy with ADA deficiency and performed 11 cycles of the infusion of the peripheral T cells transduced with retroviral vector LASN since August 8th 1995. The percentage of the peripheral blood lymphocytes carrying the transduced ADA gene has remained stable at 10% to 20% since the 4th infusion. ADA enzyme activity in his circulating T cells increased to levels comparable to 1/3 of a heterozygous carrier individual and was associated with increased T lymphocytes counts and improvement in both humoral and cellular immune function. The results obtained in this clinical study support the usefulness of T lymphocyte-directed gene transfer in the treatment of ADA deficiency.     

Increased immune response elicited by DNA vaccination with a synthetic gp120 sequence with optimized codon usage

DNA vaccination elicits humoral and cellular immune responses and has been shown to confer protection against several viral, bacterial, and parasitic pathogens. Here we report that optimized codon usage of an injected DNA sequence considerably increases both humoral and cellular immune responses. We recently generated a synthetic human immunodeficiency virus type 1 gp120 sequence in which most wild-type codons were replaced with codons from highly expressed human genes (syngp120). In vitro expression of syngp120 is considerably increased in comparison to that of the respective wild-type sequence. In BALB/c mice, DNA immunization with syngp120 resulted in significantly increased antibody titers and cytotoxic T-lymphocyte reactivity, suggesting a direct correlation between expression levels and the immune response. Moreover, syngp120 is characterized by rev-independent expression and a low risk of recombination with viral sequences. Thus, synthetic genes with optimized codon usage represent a novel strategy to increase the efficacy and safety of DNA vaccination.     

The role of the macrophage in immune regulation

The macrophage plays an important role in both the innate and acquired (humoral and cellular) immune responses. Their specialized derivatives, the dendritic cells (DCs), are uniquely potent in induction of naive T and B lymphocytes, whereas macrophages influence a range of immune responses by antigen recognition, capture, clearance and transport. They recruit haemopoietic cells to local sites of inflammation and immunity and regulate their activities. We have used various myeloid-restricted membrane antigens and receptors as markers and functional contributors to these activities, and briefly review their role in immune regulation in vivo and in vitro.     

Host immune potentiation of drug responses to a murine mammary adenocarcinoma. II. Effect of melphalan therapy on the host immune system

The role of chemotherapy in influencing tumor-specific immunity to a mouse mammary adenocarcinoma was investigated. By studying different stages of tumor growth we were able to identify several factors important to drug-induced tumor regression: (1) antibody response, (2) delayed hypersensitivity, (3) sensitivity of tumor cells to immune attack and (4) tumor burden. The presence of tumor-specific delayed hypersensitivity and circulating antibody as well as specifically armed monocytes in the tumor mass characterize the T1699 adenocarcinoma. Successful chemotherapy had previously been shown to depend on prior establishment of the above immune responses. Treatment with alkylating agents was marked in all animals by abrogation of a humoral response to the tumor when drug was given early (day 7), and was associated with poor chemotherapeutic results. Later treatment (day 10) was associated with depression of antibody titers only in the minority of animals not responding to drug and prolongation of the delayed hypersensitivity response in all treated animals. Tumors recurring following initial drug-induced regression were marked by lack of delayed hypersensitivity in the host, lack of drug response and suppression of humoral immunity following treatment. Successive passage of cells from these resistant tumors led to decreasing sensitivity to chemotherapy despite established immunity on the part of the host. The selection of tumor cells resistant to immune destruction rather than drug resistance per se appeared to pay a role. Melphalan was thus able to affect both favorably and adversely the immune factors important to drug-induced regression.     

Immunological studies of SK2 hybridoma cells microencapsulated with alginate-poly(L)lysine-alginate (APA) membrane following allogeneic transplantation

Microencapsulation of living cells or tissues has been proposed to prevent their immune destruction following transplantation. In this study, we examined whether SK2 hybridoma cells microencapsulated in an alginate-poly(L)lysine-alginate (APA) membrane (APA-SK2 cells) were immunoisolated from the allogeneic host's immune system using a cytotoxicity test. The APA membrane inhibited the activation of the host's cellular immune response, but did not prevent the production of cytotoxic antibodies against entrapped SK2 cells following allogeneic transplantation. However, the APA-SK2 cells remained vital in SK2 cell-immunized mice as well as in intact mice. We considered that complement regulatory factors which were present on cell membrane and had species-specific restriction blocked the complement-mediated cell lysis on allogeneic transplantation, since APA-SK2 cells were destroyed by rabbit anti-SK2 cell antiserum. Our results demonstrated that APA membrane could inhibit cell-cell contact between entrapped cells and the host's lymphocytes, but could not completely protect the entrapped cells from xenogeneic humoral immunity.     

Expression of complement receptors 1 and 2 on follicular dendritic cells is necessary for the generation of a strong antigen-specific IgG response

Two mechanisms could account for the impaired humoral immune response found in Cr2-/- mice. The absence of complement receptors 1 and 2 (CR1, CR2) on B cells could affect their activation. Alternatively, impaired Ag trapping by follicular dendritic cells (FDC) could affect B cell maturation into Ig-secreting or memory B cells. To compare the roles of CR1 and CR2 on B cells vs FDC in this abnormal response, bone marrow (BM) chimeric mice were generated and immunized with specific T-dependent Ags. The primary and secondary Ab response was measured. Cr2+/+ animals reconstituted with a Cr2-/- BM generated a diminished but detectable humoral immune response compared with controls. When injected with preformed immune complexes (IC), these mice maintained follicular IC localization. Cr2-/- animals reconstituted with a Cr2+/+ BM had an initial rise in the Ab titer, but were unable to maintain it as shown by a pronounced decrease in the IgG titer. This defect persisted during the secondary immune response. Follicular IC trapping was also impaired. Despite the abnormal Ab response, germinal center formation was retained in all of the chimeric animals. These experiments are the first to demonstrate an absolute requirement for CR1 and CR2 expression on FDC in the generation of a normal humoral immune response.     

Study of the effect of polybutylcyanoacrylate nanoparticles and their metabolites on the primary immune response in mice to sheep red blood cells

Polybutylcyanoacrylate nanoparticles (PBCN) and their metabolites (polycyanoacrylic acid--PCAA, and n-butanol) were compared with respect to their effects on the primary immune response of mice to sheep red blood cells (SRBC). PCAA was synthetized via a Knoevenagel reaction. Antibody production (hemagglutinins) and E-rosette-forming cells (E-RFC) were used to document the induction of antigen-specific immune response to SRBC in all immunized mice. PBCN showed a time- and dose-dependent effect on the immune response, both humoral and cellular. The inductive phase of immune response was affected preferably. The high dose of PBCN (200 mg kg(-1)) tended to suppress the immune response. This was expressed more in mice treated before antigenic stimulation. Lower dose (10 mgkg(-1)) stimulated the immune response. A significant difference was found in the effects of PBCN and their metabolites on the immune response. PCAA and n-butanol administered at doses equivalent (after lysosomal hydrolysis) to the doses applied of intact PBCN did not impair significantly the immune response. A clear time dependence and dose dependence were not observed. The study led to the hypothesis that the greater suppressive effect of PBCN, relative to either PCAA or n-butanol, or a mixture of them, is probably due to the blocking of the immunopresenting function of macrophages instead of some toxicity towards the immunocompetent cells.     

Extensive cross-reactivity of adenovirus-specific cytotoxic T cells

Although adenovirus is a major source of morbidity for immunocompromised individuals and a popular vector for gene therapy, little is known about the cellular immune responses it evokes in humans. Initial trials using adenovirus vectors have been disappointing, probably owing both to a preexisting immune response to Ad2 and Ad5, the most commonly used vector backbones, and to a response to the transgene. The former problem might be overcome by switching from the common type C adenoviruses, of which Ad2 and Ad5 are members, to other less common serotypes. Evidence for the feasibility of this approach has been provided by a rat model system. However, its success in humans depends on there being no immunological cross-reactivity between groups at the humoral or cellular level. Here, we examine the cross-reactivity of the cellular immune response to adenovirus in a human system, and find that human cytotoxic T lymphocytes (CTLs) prepared in vitro against an adenovirus from two of the six subgroups can lyse cells infected with adenoviruses from the other subgroups. Hence, the proposed use of adenovirus vectors from uncommon subgroups to evade memory immune response to subgroup C adenoviruses may not be successful. However, this same cross-reactivity indicates that adoptive transfer of CTLs generated in vitro against one adenovirus serotype may protect immunocompromised patients from infections by adenoviruses of all serotypes.     

Effect of IL-4 and IL-12 liposomal formulations on the induction of immune response to bovine herpesvirus type-1 glycoprotein D

Activation of different T-helper (Th) responses following immunisation has profound and specific influences on the development of the immune response and on the ability of a vaccine to confer protection. Since cytokines are capable of influencing the stimulation of distinct T-cell responses, their encapsulation in vaccines should modulate antigen-specific immune responses. Unfortunately, the use of cytokines in vivo is hampered by their rapid clearance and inactivation. One possible solution to this problem is the use of liposomes to entrap both cytokines and antigen. This approach will not only protect the cytokine but will also deliver the two components simultaneously to the same site. The authors examined, therefore, the immune responses elicited by systemic immunisation of mice with liposome formulations containing a truncated form of bovine herpesvirus type-1 glycoprotein D (tgD) together with IL-4 or IL-12. Subcutaneous immunisation with liposomes containing tgD and IL-12 significantly enhanced the induction of antigen-specific cellular and humoral immune responses. These responses were characterised by an increase in IFN-gamma secreting cells and the induction of tgD-specific IgG2a antibodies. In contrast, encapsulation of IL-4 into tgD-liposomes did not enhance the humoral immune response to gD but significantly influenced the development of antigen-specific IL-4 secreting cells. Our results indicated that encapsulation of IL-12 into the liposomes was necessary for the systemic adjuvant effect and demonstrated the feasibility of using liposome technology and cytokines to manipulate the development of different antigen-specific Th subsets in vivo.     

Psychological Stress and the Human Immune System: A Meta-Analytic Study of 30 Years of Inquiry.

The present report meta-analyzes more than 300 empirical articles describing a relationship between psychological stress and parameters of the immune system in human participants. Acute stressors (lasting minutes) were associated with potentially adaptive upregulation of some parameters of natural immunity and downregulation of some functions of specific immunity. Brief naturalistic stressors (such as exams) tended to suppress cellular immunity while preserving humoral immunity. Chronic stressors were associated with suppression of both cellular and humoral measures. Effects of event sequences varied according to the kind of event (trauma vs. loss). Subjective reports of stress generally did not associate with immune change. In some cases, physical vulnerability as a function of age or disease also increased vulnerability to immune change during stressors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immunomodulatory properties of porins of some members of the family Enterobacteriaceae

The outer membrane protein (OMP) preparation of Salmonella typhi was observed to have several immunomodulatory properties. Treatment of mice with an intraperitoneal injection of the OMP preparation enhanced both cellular and humoral responses of the mice to an unrelated antigen, a killed vaccine of Mycobacterium vaccae; both the delayed-type hypersensitivity (DTH) response and the antibody titers were enhanced. The predominant isotype of the antibody shifted from immunoglobulin G1 (IgG1) to IgG2a upon treatment with OMP. Treatment of mice with the OMP preparation improved the efficiency of in vitro antigen presentation by the peritoneal cells and also induced the cells to secrete interleukin-1. Treatment with the lipopolysaccharide (LPS) preparation of S. typhi had the opposite effect; i.e., the DTH response to M. vaccae was suppressed. Treatment with OMP neutralized the suppressive effects of LPS. The OMP preparation also had an enhancing effect on the innate immune mechanisms of the mice. Intraperitoneal injection of the OMP preparation enhanced the microbicidal activity of the peritoneal cells, and production of nitric oxide intermediates was stimulated. Injection of the OMP preparation into footpads of naive nonimmune mice induced a sustained hypersensitivity response that peaked at 24 h. Purified porins of the OMP preparation could induce both immunomodulation and hypersensitivity. Porins prepared from five different Salmonella strains and a strain of normal fecal Escherichia coli also exhibited immunomodulatory and hypersensitivity-inducing activities.     

Specific immune induction following DNA-based immunization through in vivo transfection and activation of macrophages/antigen-presenting cells

The initiation of an adaptive immune response requires Ag presentation in combination with the appropriate activation signals. Classically, Ag presentation and immune activation occur in the lymph node and spleen, where a favorable organ architecture and rich cellular help can enhance the process. Recently, several investigators have reported the use of DNA expression cassettes to elicit cellular and humoral immunity against diverse pathogens. Although the immune mechanisms involved are still poorly understood, plasmid inoculation represents a model system for studying immune function in response to invading pathogens. In this report, we demonstrate the presence of activated macrophages or dendritic cells in the blood lymphocyte pool and peripheral tissues of animals inoculated with DNA expression cassettes. These cells are directly transfected in vivo, present Ag, and display the surface proteins CD80 and CD86. Our studies indicate that these cells function as APC and can activate naive T lymphocytes. They may represent an important first step APC in genetic immunization and natural infection.     

Correction of neutropenia and hypogammaglobulinemia in X-linked hyper-IgM syndrome by allogeneic bone marrow transplantation

X-linked hyper-IgM (X-HIM) syndrome is a primary immunodeficiency disease characterized by defects in both cellular and humoral immunity. X-HIM is caused by mutations in the gene for CD40 ligand (CD40L), a T cell membrane protein that mediates T cell-dependent immune functions. We report the case of a 6-year-old male with X-HIM due to an intronic mutation resulting in aberrant CD40L RNA splicing and absence of detectable CD40L protein. The patient had a history of multiple infectious complications and chronic neutropenia requiring treatment with recombinant granulocyte colony-stimulating factor, and underwent allogeneic bone marrow transplantation from an HLA-matched sibling donor. Following successful engraftment, T cell CD40L expression and immunoglobulin isotype switching were reconstituted and neutropenia resolved. Allogeneic bone marrow transplantation can correct neutropenia and reconstitute immune function in X-HIM.