Genetic control of specific immune responses in inbred mice

Studies on the humoral immune response to a synthetic vaccine against Plasmodium falciparum malaria

A synthetic vaccine against the asexual blood stages of P. falciparum, the SPf 66 synthetic hybrid polymer, composed of peptides derived from three merozoite membrane proteins as well as one peptide from the sporozoite CS protein, has been developed by our group and tested in different protection assays in Aotus monkeys as well as in human volunteers. This study evaluates the humoral immune response induced by the SPf 66 protein vaccination in adult human volunteers from the Colombian Pacific coast as follows: determination of specific IgG antibody levels against SPf 66 by FAST-ELISA after each immunization; analysis of antibody reactivity with P. falciparum schizont lysates by immunoblots; and determination of the in vitro parasite growth inhibition. A clear boosting effect, dependent on time and dose, was observed in the antibody production kinetics. These antibodies also specifically recognize three proteins of the P. falciparum schizont lysate corresponding to the molecular weights of the proteins from which the amino acid sequence was derived. These sera were also capable of markedly inhibiting in vitro parasite growth.

Phenotype correction of Ir-genic control of immune response to (T,G)-A-L conjugated to synthetic polyelectrolytes

Experiments in CBA (H-2k) and C57BL/6 (H-2b) strains of mice have shown (T,G)-A-L covalently bound to synthetic polyelectrolytes possessing immunoadjuvant effect to induce a pronounced antibody and cell-mediated immune response irrespective of murine genotype. When conjugated to the polyelectrolytes (T,G)-A-L was also found to acquire the properties of a highly immunogenic thymus-independent antigen. Thus, (T,G)-A-L-synthetic polyelectrolytes conjugates manifested the effects of highly immunogenic thymus-independent antigens inducing a potent Ir-1-independent immune response. It provided for the transformation of genetically low responder individuals into high responder ones.

HLA in multiple sclerosis. Relationship to measles antibody, mitogen responsiveness and clinical course

In our study of multiple sclerosis (MS) patients we have found significant increases in the A3, B7, and DW2 antigens. We have also studied immune responses in these same patients. There was elevation of measles antibodies in MS patients positive for A3, B7, and B18 as compared to MS patients without those antigens. The first study of mitogen responsiveness (31 patients) showed a decreased response in A3, and B7 positive patients. Study of a second and a larger group (62 patients), at a different time, failed to confirm this deficiency. We propose that there is a genetically linked (HLA) T cell deficiency in some MS patients and that this deficiency results in high humoral responses to measles antigens and an evanescent (or cyclical) reduced T cell response to mitogen.

The nature and function of T-cell antigens

T-lymphocytes differ antigenically from B-lymphocytes. In the present study attempts were made to determine the role of surface antigens of T-cells, in their migration in vivo and in their response to mitogens. Exposure of thymus cells to anti-H2 sera inhibits migration to the lymph nodes (LN) to a greater extent than to the spleen. Fab fragments of H-2 antisera had only a slight effect on lymphocyte migration, inhibiting the LN-seeking stream only slightly more than the spleen-seeking stream. The interaction of Con-A with carbohydrates on the cell-surface of lymphocytes inhibits preferentially their localization in LN. Studies on the migration of lymphocytes that had localized either in the LN or spleens of primary host indicate that Con-A does not eliminate LN-seeking cells, but rather inhibits their active localization in LN. The subpopulation of lymphocytes, in both thymus and spleen that responds to Con-A was found to possess a higher H-2 antigenicity and a lower Ly and theta-antigenicity than the cells responding to PHA. Spleen cells responding to low concentrations of PHA had a relatively high H-2 antigenicity, whereas thos responding to high concentrations of PHA had a low H-2 antigenicity. Exposure of thymus cells to H-2 antiserum alone markedly inhibited their response to Con-A. Similar treatment of spleen cells had only a weak inhibitory effect.

The association of H-2 antigens and EAC receptors on the surface of peritoneal cells

The exposure of murine peritoneal cells to anti-H-2 sera results in a diminished expression of H-2 antigen on the cell surface. Concomitant with this "H-2 modulation" the capacity of macrophages to bind sheep red blood cells coated with antibody and complement (EAC) was markedly diminished. In contrast, there was no change in the capacity of modulated macrophages to bind sheep red blood cells coated with antibody alone (EA). Antibodies to K end H-2 specificities were more effective in reducing the binding of EAC than antibodies to D end H-2 specificities. Exposure of peritoneal cells to O or Ly antisera had no effect on the formation of EAC rosettes. Exposure of peritoneal cells to anti-H-2 sera, under conditions which would not allow modulation of H-2 antigens, also prevented the reduction of EAC binding. Thus, the EAC receptors and H-2 antigenic specificities seem to be closely related on the surface of peritoneal cells, but constitute distinct cell surface structures. Preliminary evidence indicates that vinblastine, a microtubule depolymerizing agent, may disrupt the close association of EAC receptors and H-2 antigens. It is suggested that the association of EAC receptors and K end H-2 determinants on the membrane of macrophages may have implications for the regulation of the immune response by H-2-linked Ir genes.