Protection of cotton rats against human respiratory syncytial virus by vaccination with a novel chimeric FG glycoprotein.

The cotton rat model of experimental human respiratory syncytial virus (RSV) infection was used to study the efficacy of FG, a novel chimeric glycoprotein which was expressed in insect cells using a baculovirus vector. FG contained the extracellular regions of the F (fusion) and G (attachment) glycoproteins of RSV. Vaccination with FG resulted in induction of neutralizing antibody and was correlated with protection of lung tissue from RSV challenge against both serogroup A and B virus strains. Both crude FG taken from supernatants of insect cells and affinity-purified FG were immunogenic and active against RSV. FG vaccination was effective by three routes of administration, following a single dose, and when administered with different adjuvants.

Autoimmunity in Chagas' disease: specific inhibition of reactivity of CD4+ T cells against myosin in mice chronically infected with Trypanosoma cruzi.

In this study, we assessed the proliferative response of T cells from mice chronically infected with Trypanosoma cruzi to actin, myosin, or T. cruzi soluble antigen (SA). We report here that CD4+ T cells from mice chronically infected with T. cruzi proliferated in response to myosin but not to actin, whereas cells from naive mice did not proliferate against any of the antigens tested. Antisera raised against myosin- or SA-activated T cells specifically inhibited respectively, the myosin or SA in vitro proliferative response, whereas the response to unrelated antigen remained unimpaired. Sera from chronically infected mice failed to show any significant inhibitory activity. The above findings suggest that autoreactive and T. cruzi-reactive T cells belong to different, perhaps nonoverlapping, compartments of the immune cell repertoire of mice chronically infected with T. cruzi. The failure of infected mice to trigger the suppressive mechanisms described here might be the primary immune defect leading to breakdown of self-tolerance and unopposed, perhaps tissue-damaging, autoimmunity in experimental Chagas' disease.

Increased production of cytotoxic macrophage progenitors by Lactobacillus casei in mice.

Heat-killed Lactobacillus casei YIT9018 (LC9018), when administered intravenously to normal mice, induced increase in Mac-1+ cells and Mac-2+ cells but not in Mac-3+ cells in spleen. The number of both populations changed in the same time course and was maximal 14 d after the administration. To know the effect of LC9018 on hematopoietic progenitor level, we examined the number of macrophage colony-forming cells (M-CFC), granulocyte-macrophage CFC (GM-CFC), and colony-forming units in spleen (CFU-S) in bone marrow 3 d after the administration. LC9018 stimulated the proliferation of M-CFC but not that of GM-CFC and CFU-S. LC9018-induced M-CFC were similar to normal M-CFC in dependence on macrophage colony-stimulating factor (M-CSF) and buoyant density. M-CFC-derived macrophages cultured in the presence of M-CSF expressed Mac-1 and Mac-2 but not Mac-3. They showed cytotoxic activity against syngenic tumor cells, Meth A, via direct contact, when assayed by using an in vitro colony inhibition assay or an in vivo Winn test. These results indicate that LC9018 stimulates the proliferation of cytotoxic macrophage progenitors in bone marrow and induces their differentiation in spleen. These effects may be one of the ways in which LC9018 suppresses tumor growth.

CD44 contributes to T cell activation.

We demonstrate here that the CD44 molecule, which mediates lymphocyte adhesion to high endothelial venules (HEV), is also involved in the delivery of an activation signal to the T cell. We have produced a CD44 mAb (H90) which is able to block the binding of lymphocytes to high endothelial venules. H90 had no effect on [3H]TdR incorporation of whole PBL stimulated by lectins, allogeneic cells, or CD3 mAb in the soluble phase; in contrast, it strongly increased [3H]TdR incorporation of PBL stimulated by CD2 pairs of mAb or by CD3 mAb linked to the plastic culture plates, when purified T cells were used, H90 mAb could efficiently induce them to proliferate after a primary signal of activation delivered via cross-linked CD3 or via CD2, an effect mediated by Il-2 synthesis and Il-2R expression. Thus, the effect of H90 mAb resembles the mitogenic effect of CD28 "9.3" mAb. However, several results show that CD28 and CD44 mediate different signals to the T cells: i) in contrast to CD28 mAb, CD44 mAb cannot complement the signal delivered by a soluble CD3 mAb, lectins, or PMA; ii) CD44 mAb, at the difference of CD28 mAb, cannot induce CD3+ thymocytes to proliferate in conjunction with a first signal provided via cross-linked CD3 or via CD2; iii) F(ab) fragments of H90 were efficient, whereas divalent fragments of CD29 9.3 mAb are required to produce activation signals; and iv) CD44 and CD28 mAb produce a very strong synergistic effect on T cell proliferation. These results fit with previous ones showing that endothelial cells can play the role of accessory cell in T cell activation and that a hierarchy of signaling can be delivered to T cells via CD3 and CD2.

Antibody responses and protection in mice immunized with herpes simplex virus type 1 antigen immune-stimulating complex preparations.

The formation of immune-stimulating complexes (iscoms) obtained by mixing the glycoside Quil A with an antigen preparation derived from herpes simplex virus type 1 (HSV-1)-infected cell cultures using a zwitterionic detergent is described. The HSV-1 antigen preparation incorporated into iscoms elicited significantly greater antibody responses in mice than the same preparation administered together with aluminium hydroxide gel, and provided complete protection against HSV-1 or HSV-2 lethal, systemic challenge infection in animals given a single dose containing 5 micrograms of protein. The HSV-1 iscom preparation also provided significant protection in mice against local reactions following challenge with HSV-1 by skin scarification.

Use of a synthetic peptide adjuvant for the immunization of baboons with denatured and deglycosylated pig zona pellucida glycoproteins.

Baboons were immunized using a synthetic peptide adjuvant with two purified pig zona pellucida glycoproteins. The major zona pellucida glycoprotein (ZPI) was purified by preparative isoelectric focusing, and the 80 K deglycosylated zona pellucida protein (ZPIII) was purified by preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis. The immunogenicity as well as the antigenicity of these proteins were evaluated by characterizing antibodies using the enzyme-linked immunoassay and by immunoblotting of zona pellucida proteins separated by high-resolution two-dimensional polyacrylamide gel electrophoresis. Both groups of animals developed antibodies that recognize the major zona pellucida glycoprotein, (ZPI) and immunoblotting procedures provide evidence that two of the major porcine zona pellucida glycoprotein families (ZPI and ZPIII) contain shared antigenic determinants. The animals immunized with ZPI showed decreased levels of estrogen throughout their menstrual cycles, and two of the animals ceased ovulation. All animals in the group immunized with ZPIII had a significant reduction in the numbers of antral follicles as compared with control animals. Although ovarian cyclicity was not altered significantly within a few months after immunization, two of the five animals in this group became amenorrheic by 8 months. Histologic analysis of ovarian tissue shows that follicles were absent or frequently abnormal in animals of both groups following long-term immunization. These studies demonstrate that the synthetic adjuvant is effective in inducing antibodies (to purified zona pellucida glycoproteins) that recognize antigenic determinants to either denatured or deglycosylated zona pellucida glycoproteins, and that some of these antibodies may interfere with normal ovarian function.

A monoclonal antibody to the IL-1 beta peptide 163-171 blocks adjuvanticity but not pyrogenicity of IL-1 beta in vivo.

The synthetic fragment VQGEESNDK, corresponding to the amino acid sequence in position 163-171 of human IL-1 beta, possesses the immunostimulatory but not the pyrogenic activity of the mature IL-1 beta polypeptide in vivo. To assess the relevance of this domain of IL-1 beta for its biologic activities, a mAb was raised against the synthetic peptide 163-171. The mAb Vhp20 could effectively recognize human rIL-1 beta in RIA and immunoblotting. In vivo, the mAb Vhp20 was able to selectively inhibit the immunostimulatory activity of IL-1 beta, but it could not affect the fever-inducing capacity of IL-1 beta. It is proposed that functional domains could be identified in the human IL-1 beta protein and that the fragment in position 163-171 is of major importance for the adjuvant capacity of the entire molecule, but irrelevant to its pyrogenic activity.

[Polyclonal B-cell activation by so-called immunopotentiation (immunostimulants)]. / Polyklonale B-Zellaktivierung durch sogenannte Umstimmungsmittel ("Immunstimulantien").

Immuno-augmentation with substances of bacterial origin was studied in vitro for its ability to induce polyclonal B-cell activation. Biostim, Broncho-Vaxom, Omnadin, Paspat and OK 432 were compared for their B-cell mitogenicity with classical polyclonal B-cell activators (Staph. aureus Cowan I, KlebsM, Pokeweed mitogen). B-cell mitogenicity, as measured by 3H-thymidine incorporation into proliferating blood B-cells, was not induced by any of the studied preparations. On the other hand, OK 432 produced a T-cell dependent and Biostim a T-cell independent blood B-cell differentiation in immunoglobulin producing cells. However, the extent of immunoglobulin production was clearly less than with the polyclonal B-cell activator KlebsM. These results demonstrate that, in some of the preparations, in vivo polyclonal B-cell activation can be expected to occur.

Prophylactic activity against Sendai virus infection and macrophage activation with lipophilic derivatives of N-acetylglucosaminylmuramyl tri- or tetrapeptides.

The efficacy of N-acetylglucosaminyl-beta (1----4)-N-acetylmuramyl tri- or tetrapeptides (GM) and the lipophilic derivatives for host augmentation against Sendai virus infection and for macrophage activation in vitro was examined. The anti-infectious activities of GM derivatives were shown to increase with the chain length of the fatty acid combined with the diaminopimelyl group. When the macrophages were activated with 1 U ml-1 murine interferon gamma (IFN-gamma) and 0.001 microgram ml-1 GM derivatives, the cytocidal ability of macrophages depended on the length of the side chain, and exhibited a positive relationship with the anti-infectious activity of GM derivatives against Sendai virus infection. These results indicated that the increment of lipophilicity of GM derivatives would play an important role in the anti-infectious activity and macrophage activation in vitro.

Immunoregulation through CD8 (Ly-2): state of aggregation with the alpha/beta/CD3 T cell receptor controls interleukin 2-dependent T cell growth.

The activation of T lymphocytes by an antigenic challenge requires that the CD3 T cell receptor alpha/beta (TcR) is bound to an appropriate ligand, i.e. major histocompatibility complex antigen, on an antigen-presenting cell. In addition, numerous studies suggest that the accessory molecules CD4 and CD8 participate in the recognition process, and may have inhibitory as well as augmenting effects depending on the ways in which they participate. In the present study we attempt to define the conditions by which CD8 exerts enhancing and inhibitory effects on resting CD8+ T cell activation, and which parameters of activation are regulated through participation of CD8/CD4. We find that experimental procedures leading to TcR-CD8 aggregation induce T cell activation whereas experimental procedures preventing TcR-CD8 aggregation inhibit T cell activation. CD8/CD4-induced variations in the extent of T cell activation are apparent as variations in interleukin 2 (IL 2)-dependent growth and in the number of blastoid cells bearing IL 2 receptors. Inhibition of CD8+ T cell activation is successful only if the majority, if not all CD8 molecules are occupied by soluble antibody. This latter finding argues against the suggestion of other groups that CD8 may be a receptor for negative signaling. Rather, the results support the alternative notion that a basal level of TcR-CD8 aggregation, existing in the resting state or induced by TcR-ligand interaction, is an essential prerequisite for CD8+ T cell activation. Enhancement or depression of this basal level of aggregation causes facilitation or inhibition, respectively, of activation. This may be a mechanism for the regulation of IL 2-dependent clonal expansion of T cells in immune responses.

Immunoadjuvant action of liposomes: comparison with other adjuvants.

Dehydration-rehydration vesicles (DRV liposomes) composed of equimolar phospholipid and cholesterol and containing bovine serum albumin (BSA) were used together with free BSA to immunize Balb/C mice. Primary and secondary immune responses (IgG1) to the liposomal antigen, as measured by ELISA in mouse sera, were similar for egg phosphatidylcholine (PC) and distearoyl phosphatidylcholine (DSPC) DRV, and much greater than those elicited by free BSA. The adjuvanticity of PC DRV was compared with that of aluminium salts (alum), complete Freund's adjuvant (CFA) and N-acetyl muramyl-L-threonyl-D-isoglutamine ([Thr1]MDP), the latter used as such or in a liposome form co-entrapped with the antigen. DRV (with or without co-entrapped [Thr1]MDP), and alum were equally strong in producing primary and secondary immune responses (IgG1) to BSA. Such responses were significantly higher than those achieved with CFA and [Thr1]MDP alone. The implications of these results for the potential role of liposomes as immunological adjuvants in vaccines are discussed.

[Changes in the rosette-forming capacity of peripheral blood lymphocytes in patients with ischemic heart disease after administration of atherogenic lipoproteins]. / Izmenenie rozetkoobrazuiushchei sposobnosti limfotsitov perifericheskoi krovi bol'nykh ishemicheskoi bolezn'iu serdtsa pod deistviem lipoproteidov aterogennykh klassov.

Low-density lipoproteins, isolated from the serum of patients with hypercholesterolemia (dislipoproteinemia, type IIa), increased significantly the number of active and recovered rosette-forming cells (RFC) at incubation with lymphocytes of coronary patients. The use of lipoproteins, belonging to all atherogenic classes, did not essentially alter lymphocyte ability to form total E-RFC. Purified apolipoprotein B reduced lymphocyte capacity for active rosette formation.

[Clinico-immunologic effectiveness of chlorophyllypt in the treatment of acute destructive pneumonia]. / Kliniko-immunologicheskaia éffektivnost' khlorofillipta pri lechenii ostroi destruktivnoi pnevmonii.

An attempt has been made to replace antibiotics by chlorophyllypt (0.25 per cent solution in physiological sodium chloride solution administered by intravenous drip). The clinical, laboratory and X-ray parameters in 22 patients treated by this drug normalized in earlier terms than those in 19 patients who received the traditional antibiotic therapy. Chlorophyllypt was found to have the immunocorrective effect manifested by the normalization of the T-lymphocyte number and their theophylline-resistant subpopulation. No such an effect was achieved when broad-action antibiotics were used.

Role of pertussigen (pertussis toxin) on the mouse protective activity of vaccines made from Bordetella species.

Pertussigen [pertussis toxin (Ptx)] from Bordetella pertussis, when detoxified, induces protection in mice to intracerebral challenge (ic) with virulent B. pertussis. In its native form, minute nonprotective doses promote the development of immunity induced by other antigens of B. pertussis. As little as 4 ng of Ptx, given with a nonprotective dose of 8 X 10(7) killed cells of the phase III Sakairi strain, promoted detectable protection to ic challenge. Native Ptx in doses of 0.4 to 400 ng did not protect mice, and vaccines made from strains not producing Ptx induced only weak protection. The marked enhancing action of Ptx was also observed with 5 micrograms of purified filamentous hemagglutinin and with vaccines made from other species of the Bordetella genus, such as B. parapertussis and B. bronchiseptica, but it was not observed with B. pertussis endotoxin. In addition, Ptx was still effective when given as late as 7 days after the vaccine. Antibodies to surface antigens of the challenge strain were demonstrated in sera of mice immunized with vaccines prepared with the different Bordetella species tested, but antibodies to Ptx were detected only in the sera of mice immunized with the wild-type B. pertussis strains. Glutaraldehyde detoxified Ptx does not have this action. Pretreatment of normal mice with Ptx, also enhanced the protective action of a mouse antiserum to a wild-type strain of B. pertussis. These observations show that antigens other than Ptx are responsible for the protection, and that Ptx acts non-specifically to enhance the mouse protective action of those antigens.

Protection against experimental allergic encephalomyelitis with complete Freund's adjuvant is unaffected by prostaglandin synthesis inhibition.

Pretreatment with complete Freund's adjuvant blended with aluminium hydroxide (ALU-CFA) prevents the clinical as well as histological manifestation of experimental allergic encephalomyelitis (EAE) in Lewis rats. Suppression of prostaglandin biosynthesis with the cyclooxygenase inhibitor piroxicam (10 mg/kg body weight) from day 2 before to day 17 after EAE induction could not restore responsiveness in pretreated animals. In contrast piroxicam increased ALU-CFA-induced suppression of autoantibodies against myelin basic protein. In controls not pretreated with ALU-CFA, clinical signs of EAE were attenuated by piroxicam, whereas mononuclear infiltration of the brain remained unchanged. Therefore it is unlikely that prostaglandins exert an important function in the regulation of immune responses in this model of autoimmunity.

[Cells-boosters as the modulators of immunogenesis]. / Kletki-usiliteli kak moduliatory immunogeneza.

In the course of mouse immune response to ram erythrocytes, cells capable of enhancing immune and proliferative response (enhancing cells, or EC) are shown to appear in the spleen. The EC effect is antigen-unspecific. Cycloheximide (CH), an inhibitor of protein synthesis, speeds up EC development, which is associated with a greater immune response. In vitro CH treatment of mouse spleen cells (SC), for 3 hours at 37 degrees C, CH taken in a concentration of 1-3 micrograms/ml, resulted in in vitro induction of EC, capable of enhancing proliferative response to PHA and recombinant IL-2 in normal SC and increasing immune response to ram erythrocytes. Glutaric aldehyde fixation of EC was not reflected in their immunostimulating activity, either in vivo, or in vitro. The data obtained point to the significance of CH-induced changes in membrane-associated structures in mediating EC effect. It is assumed that the agents, altering the expression of functionally-significant structures (membrane-linked mediators and auxiliary intercellular interaction molecules) on cell surface, may be used for extracorporeal treatment of lymphoid cells to be eventually re-introduced into the body to control immunologic disorders.

Nematospiroides dubius: influence of adjuvants on immunity in mice vaccinated with antigens isolated by affinity chromatography from adult worms.

Five adjuvants were examined for their ability to potentiate the immune response of mice to soluble antigens from adult Nematospiroides dubius prepared by affinity chromatography against antibodies from repeatedly infected mice as ligands (IMIgAg). Immunized mice were better protected against N. dubius by IMIgAg injected intraperitoneally with either pertussigen (75%) or aluminium hydroxide (Alum) (67%) as adjuvants than with Freud's complete (54%) or incomplete adjuvants (31%). Protection was correlated with elevated specific antibody values and with cellular responses. Quil A was toxic to recipient mice at the concentration used. Alum may be a more practical adjuvant than pertussigen, which may activate protective immunity only in specific recipient genotypes and oil-based adjuvants which appear to be less efficient, to vaccinate mice with soluble parasite antigens.