Effect of levamisole on the cellular and humoral immunity indices in patients with chronic brucellosis

In chronic brucellosis patients receiving levamisole and placebo the dynamics of quantitative and functional characteristics of cell-mediated and humoral immunity have been studied. The immunomodulating effect of levamisole, manifested only in the process of treatment by a rise in the number of circulating lymphoid cells, their functional capacity, a decrease in the disproportion of immunoregulatory cells and the amount of circulating immune complexes, has been established. The positive dynamics of immunological characteristics have been found to improve both immediate and remote results of the clinical effectiveness of levamisole.     

Reconstitution of in vivo cell-mediated lympholysis responses in aged mice with interleukin 2

Advancing age is accompanied by declining immune potential. Both humoral and cellular immune responses are diminished in aged humans and experimental animals. A major lesion preventing effective T cell-mediated responses is the lack of interleukin 2 (IL 2) synthesis in aged mice. Addition of IL 2 can effectively reconstitute in vitro T cell-dependent humoral and cell-mediated immunity. These results have been extended, demonstrating that IL 2-containing lymphokine preparations when administered with antigen can restore the ability of aged mice to generate cytotoxic T lymphocytes in vivo. Furthermore, IL 2 has been identified as the active component of these lymphokine preparations through the use of purified human IL 2 prepared by recombinant DNA and gene cloning technology. The cloned IL 2 is highly effective in enhancing the immune responses of aged animals both in vitro and in vivo.     

Dynamics of the humoral immunity indices in patients with subacute brucellosis being treated with levamisole

The dynamics of the main characteristics of humoral immunity in patients with subacute brucellosis, receiving levamisole and placebo, has been studied. Levamisole produced an immunomodulating effect manifested by an increase in the number of B-lymphocytes and a drop in the level of circulating immune complexes. Levamisole did not essentially influence the content of serum immunoglobulins and specific antibodies.     

Effect of testosterone on T cell-mediated immunity in two species of Mediterranean lacertid lizards

One of the primary assumptions of the immunocompetence handicap hypothesis is that testosterone has an immunosuppressive effect, but conflicting results have been reported in a variety of bird species concerning the effect of testosterone on the humoral and the T cell-mediated components of the immune system. The T cell-mediated component of the immune system is particularly important during the breeding season, because the likelihood of injury during sexual competition is high and T cell-mediated immunity is essential for healing wounds and resisting infection. In this study we examined the effect of experimentally increased levels of testosterone during breeding season on T cell-mediated immunity in male lizards of two Mediterranean lacertid species, Psammodromus algirus and Acanthodactylus erythrurus. The hormonal treatment significantly increased testosterone of the experimental individuals. T cell-mediated responses to phytohemagglutinin stimulation were significantly suppressed in testosterone-treated males of both species. Furthermore, there was a significant negative relationship between individual variability in T cell-mediated responsiveness and plasma testosterone concentration. The present study is the first to demonstrate testosterone-induced suppression of T cell-mediated immunity in lizards.     

The immunoregulatory properties of reaferon

The influence of human recombinant alpha-interferon (reaferon) on cell-mediated and humoral immune response has been studied. Experimental facts on the blast transformation of lymphocytes, humoral immune response and the reaction of delayed hypersensitivity are presented. The study has shown that reaferon possesses the main immunoregulatory properties, characteristic of natural human leukocytic alpha-interferon. Manifestation of these properties depends on the dose of preparation and the time of its use.     

Experimental evaluation of the brucellosis therapeutic vaccine efficacy

Use of antibiotics can't completely solve the problem of brucellosis treatment, especially its chronic forms, because antibacterial preparations do not eliminate main pathogenetic factor of the disease--sensibilization of the macroorganism. It makes actual the question about complex immuno- and antibacterial therapy. Long-term clinical experience proved high effectiveness of a therapeutic brucellosis vaccine. Earlier this preparation was manufactured in Research Institute of Vaccines and Sera in Tbilisi (Georgia). To date new composition of components of the vaccine has been developed, and manufacturing and control methods have been improved. Marked desensitizing effect of the vaccine and its stimulatory action on cellular and humoral immunity has been observed. In 2002 technological normative documentation for manufacturing and use of the vaccine was developed in the Research Institute of Microbiology (Kirov) and production of the vaccine began.     

T mu and T gamma-lymphocyte counts and their ratio in patients with brucellosis

The levels of circulating T mu- and T gamma-lymphocytes in brucellosis patients have been studied in relation to the clinical form of the disease, the severity of the process and the allergic transformation of the body. A decrease in the content of lymphocytes, affecting mainly T mu-cells and less commonly T gamma-cells, as well as a change in their ratio has been revealed. The level of this decrease depended on the clinical form of brucellosis, the severity of the course of acute and subacute brucellosis, the phase of chronic brucellosis and the allergic transformation of the body. The disproportion of immunoregulating cells in brucellosis, revealed in this study, is supposed to be of pathogenetic importance.     

Cellular and humoral immunity and nonspecific resistance factors in chronic opisthorchiasis patients during dispensary observation

In 116 patients with opisthorchiasis running a cholecystocholangitic variant of the disease course, the characteristics of nonspecific resistance (complement, lysozyme, properdin), cell-mediated and humoral immunity (T- and B-lymphocytes, T gamma-, T mu-, O-, D-, A-cells and auto-rosette-forming cells, IgG, IgA and IgM) have been studied. Essential changes in these characteristics before and after treatment, as well as at the remote periods of dispensary observation, have been established.     

Is the delayed-type hypersensitivity observed after a low dose of antigen mediated by helper T cells?

Unprimed murine spleen cells, when cultured at different densities but in the presence of the same concentration of antigen, are induced to mount different classes of response. Three modes of behavior are found. A low density does not support the induction of any response, a medium density supports a transient IgM and substantial delayed-type hypersensitivity (DTH) response, and a high density only supports a sustained IgM response. This in vitro system has been used to show that a low density of cells, when complemented with irradiated specific T cells, can mount a DTH response, and thus behave as a medium density of cells. These observations show that the induction of DTH requires helper T cells, and that a medium density, in contrast to a low density, allows sufficient collaboration to obtain a DTH response. The observation that a high density only mounts a sustained humoral response suggests that the formation of more helper T cell-dependent signals than the number generated at a medium density may be required to induce a sustained humoral response as well as the suppression of DTH. This hypothesis is supported by the findings that the response by a medium density of cells is dramatically affected by the addition of irradiated antigen-specific helper T cells; the DTH response is specifically suppressed and a sustained humoral response is observed. These results show that the induction of a humoral response is more T cell dependent than the induction of a cell-mediated response and provides an in vitro means for switching a cell-mediated response to a humoral one in an antigen-specific manner. Observations are also presented to show that the production of antibody by a high density of cells is not a prerequisite for the suppression of DTH reactivity.     

Protective and therapeutic efficacy study of divalent fusion protein rL7/L12-Omp25 against B. abortus 544 in presence of IFNγ

Brucella as intracellular pathogen requires a coordinate interaction between Th1 subset of gamma interferon-secreting CD4 T cells and CD8 T cells for optimal protective immunity. It was previously recognized that L7/L12 as T cell-reactive antigen from the pathogen. On other hand, Omp25 was found as another antigen to provide protection against the Brucella infection by eliciting both Th1 and Th2 type of immune responses in mice. Here, we analyzed the prophylactic and therapeutic efficacy of a divalent fusion protein (rL7/L12-Omp25) comprising these two promising immunogens of Brucella in the presence of murine IFN-gamma in mice against B. abortus 544 challenge. rIFN-gamma with rL7/L12-Omp25 resulted in superior immune response when compared to the animal vaccine strain B. abortus S19. The vaccine candidate caused dominance of IgG1 over IgG2a and upregulated cytokine secretion (IFN-gamma, TNF-α, and IL-10) among immunized mice. Moreover, the antigen in combination with murine IFN-gamma elicited stronger cell-mediated immune response among the immunized animals when compared to standard vaccine (S19). The registered log protection unit among challenged mice with B. abortus 544 pathogen was 2.16, p = 0.0001 when rL7/L12-Omp25 was administered alone and 2.4, p = 0.0001 when it was administered along with rIFN-gamma. However, the molecule upon administration with murine IFN-gamma imparted very minimal or no therapeutic effect against brucellosis. To conclude, our study demonstrates the potential of rL7/L12-Omp25 as an immunogen of prospective and efficient prophylaxis as it is capable of eliciting both cell-mediated and humoral immune responses against brucellosis.

     

A retrospective evaluation of the role of T cells in the development of malaria vaccine

Due to the fact that the life cycle of malaria parasites is complex, undergoing both an extracellular and intracellular phases in its host, the human immune system has to mobilize both the humoral and cellular arms of immune responses to fight against this parasitic infection. Whereas humoral immunity is directed toward the extracellular stages which include sporozoites and merozoites, cell-mediated immunity (CMI), in which T cells play a major role, targets hepatic stages - liver stages - of the parasites. In this review, the role of T cells in protective immunity against liver stages of the malaria infection is being re-evaluated. Furthermore, this review intends to address how to translate the findings regarding the role of T cells obtained in experimental systems to actual development of malaria vaccine for humans.     

Immunogenicity of surface and capsular antigens of Burkholderia

Study showed that five (C3, C6, C9, C10, C11) out of ten chromatographic fractions of surface and capsular antigens of B. mallei significantly stimulated cell-mediated immunity that manifested in activation of delayed hypersensivity reactions (DHS) and phagocyteability of noncapsulated avirulent strain of B. mallei with added surface and capsular antigenic complexes. Other fractions did not stimulate cell-mediated immunity, furthermore, fraction C8, which contained capsular biopolymer with mass of 200 kD (Ar8), was characterized by immunosuppressive effect on DHS and phagocytosis. Observed stimulation of cell-mediated immunity by fractions referred above has been confirmed by assessment of their protective effects on the model of experimental melioidosis in white rats. Relationship between markers of humoral and cell-mediated immunity, including markers of specific response, was not observed.     

A DNA vaccine prime followed by a liposome-encapsulated protein boost confers enhanced mucosal immune responses and protection

A variety of DNA vaccine prime and recombinant viral boost immunization strategies have been developed to enhance immune responses in humans, but inherent limitations to these strategies exist. There is still an overwhelming need to develop safe and effective approaches that raise broad humoral and T cell-mediated immune responses systemically and on mucosal surfaces. We have developed a novel mucosal immunization regimen that precludes the use of viral vectors yet induces potent T cell responses. Using hepatitis B surface Ag (HBsAg), we observed that vaccination of BALB/c mice with an i.m. HBsAg-DNA vaccine prime followed by an intranasal boost with HBsAg protein encapsulated in biologically inert liposomes enhanced humoral and T cell immune responses, particularly on mucosal surfaces. Intranasal live virus challenge with a recombinant vaccinia virus expressing HBsAg revealed a correlation between T cell immune responses and protection of immunized mice. A shortened immunization protocol was developed that was successful in both adult and neonatal mice. These results support the conclusion that this new approach is capable of generating a Th-type-1-biased, broad spectrum immune response, specifically at mucosal surfaces. The success of this design may provide a safe and effective vaccination alternative for human use.     

Changes in blastogenic responses and antibody titers of mice infected with Toxoplasma gondii]

This study was performed to observe the cell-mediated and humoral immune responses in mice which were infected with Beverley, Fukaya and ME49 strain of Toxoplasma gondii, respectively. The blastogenic responses of splenocytes using [3H]-thymidine and serum antibody titers were measured weekly up to 10 weeks after infection. The blastogenic responses of splenocytes treated with concanavalin A and Toxoplasma lysate were significantly declined in the 3 strain groups as compared with the non-infected group (p less than 0.05), however lipopolysaccharide-treated blastogenic responses were not significantly different between infected and non-infected groups. The serum IgG antibody titers in the three infected groups increased from 2 weeks after infection, and the serum IgM antibody titers increased until 4 weeks after infection. No significant differences were revealed in blastogenic responses and serum antibody titers among the 3 groups. The present study suggested that cell-mediated immune responses were involved in T. gondii infected mice and blastogenic responses of T lymphocytes were inhibited in acute T. gondii infection.     

The effect of an immune antibacterial plasma and a donor leukocyte mass on the immune system of patients with suppurative-septic processes

The influence of immune antistaphylococcal, anti-Proteus and anti-Pseudomonas aeruginosa plasma and donor leukocyte mass on some humoral and cell-mediated immunity characteristics in patients with purulent and septic diseases has been studied. The study has shown that treatment with immune plasma leads to an increase in the amount of circulating T lymphocytes and in the concentration of IgA, IgM and IgG, to the activation of phagocytosis and to an increase in the titers of the corresponding antimicrobial antibodies simultaneously with a decrease in the content of bacterial antigens in the blood serum. Treatment with donor leukocyte mass has also been found to lead to an increase in the concentration of T lymphocytes and immunoglobulins, to enhance the functional activity of phagocytizing neutrophils and to promote the normalization of the content of leukocytes in the peripheral blood. The use of these preparations as stimulating agents in the treatment of patients having purulent septic diseases and, simultaneously, low cell-mediated immunity characteristics is recommended.     

Modulation of immune responses by suppressor T cells.

The activity of suppressor T cells has been demonstrated in almost every phase of the immune response. These regulatory cells modulate both humoral and cell-mediated immunity utilizing antigen-specific and nonspecific mechanisms. For comparative purposes two murine models are described, the nonspecific suppressor T cell stimulated by the mitogen concanavalin A and the antigen-specific suppressor T cell stimulated by injection of the synthetic terpolymer acid 60-L-alanine30-L-tyrosine10 (GAT) in nonresponder mice. These two T cells are similar to expression of Ly alloantigens, ability to inhibit antibody responses, and the mediation of suppression, at least in part, by soluble products. However, differences in radio-resistance and antigenic specificity of the suppressor T cells, as well as differences in molecular characteristics of the soluble factors and their targets suggest that these T cells regulate the immune response by different mechanisms. The relationship of these two suppressor T cells to other nonspecific and antigen-specific suppressor T cells is discussed.     

The T mu- and T gamma-lymphocyte count and their ratio in patients with brucellosis of various focal natures

The content of T mu- and T gamma-lymphocytes and their ratio in patients having subacute and chronic brucellosis with different foci of infection have been studied. The relationship between the decrease in the levels of T mu- and T gamma-cells and the clinical form of the disease and its clinical manifestations, such as polyarthritis, has been established. Manifestations of disturbances in the T mu-cell/T gamma-cell ratio were more pronounced in patients with subacute brucellosis in whom the lesions of the osteoarticular system prevailed. The detected changes in the counts of immunoregulatory cells in brucellosis are assumed to be of pathogenetic importance.     

The effect of T cell growth factor on the generation of cytolytic T cells.

The development of cytotoxic effector cells through primary allogeneic mixed tumor-lymphocyte culture (MTLC) was found to be accompanied by the production of T cell growth factor (TCGF). Addition of supplemental TCGF to MTLC resulted in the generation of significantly greater quantities of effector cells, and these effector cells displayed augmented cytotoxic activity. The TCGF-induced effect could not by duplicated by the addition of fresh medium or a mitogenic concentration of concananvalin A. Although TCGF augmented the proliferation of antigen-nonreactive cells, antigen-reactive cells appeared to be preferentially stimulated by TCGF. Finally, it was shown that depletion of TCGF from MTLC resulted in an impairment of proliferation and differentiation of cytotoxic effector cells. These findings demonstrate that soluble factors are involved in the regulation of in vitro cell-mediated immune responses in an analogous manner to similar factors that have been shown to regulate humoral immune responses. Therefore, the forces affecting TCGF production may modulate the amplitude of a T cell-mediated cytolytic response.     

The importance of different murine cell types in the immunopotentiation produced by amphotericin methyl ester.

Amphotericin R (AmB) or its methyl ester (AME) are potent stimulants of humoral and cell-mediated immunity in mice. When AME is injected simultaneously with antigen, it augments humoral immunity by expansion of the primary as well as the memory B cell pool. The most consistent and dramatic effect of amphotericin on humoral immunity is the enhancement of secondary IgG responses. This effect on the IgM-IgG switch mechanism depends on T cells and is reduced following thymectomy on adult mice. The route and timing of amphotericin administration also have dramatic quantitative, effects on immunopotentiation. Neither polyclonal B cell activation nor stimulation of antigen uptake in vitro by peritoneal macrophages was observed following intraperitoneal injection of AME. A tentative hypothesis is that antigen-stimulated T cells are important sites of the immunostimulant effects of AME on murine immune responses.