Studies on the control of antibody synthesis. XVI. Effect of immunodepression on antibody affinity

The relationship between depression in the magnitude of the immune response and a decrease in affinity of the antibody produced was examined in three different models of immuno-depression (B-cell clonal deletion tolerance, specific suppressor T-cell activity, and anti-genie competition). In B-cell clonal deletion tolerance and in antigen-specific, suppressor T-cell-mediated immunodepression, a small decrease in magnitude (50% or less) is associated with a marked decrease in high-affinity, plaque-forming cells. In contrast, with nonspecific immunodepression, due to antigenic competition, a depression in affinity is only seen when there is a marked (85%) reduction in the magnitude of the response. The results are consistent with the view that when the mechanism of immunodepression involves interaction of antigen with antigen-specific B cells there is a disproportionate loss of high-affinity, antibody-producing cells relative to the decrease in magnitude. In contrast, with nonspecific immuno-depression, where the decrease in affinity is presumably due to inefficient expansion of high-affinity clones, an effect on affinity is only observed in association with a marked depression in the magnitude of the response.     

Effect of a bone marrow stimulator of antibody producers on virus-specific antibody formation in animals infected with flaviviruses

The injection of the marrow stimulator of antibody-producing cells (SAPC) into animals infected with Japanese encephalitis and tick-borne encephalitis viruses stimulated the formation of virus-specific antibodies in the infected animals, increasing antibody production 8- to 16-fold. Such SAPC-induced stimulation of the formation of virus-specific antibodies is observed in cases of both acute and chronic virus infection. The prospects of using the preparation of SAPC are discussed.     

The comparative effects of actinomycin D, imuren and hydrocortisone on interferon and antibody formation in mice]

A single dose of actinomycin-D (2.5 mg/kg body wt) reduced the interferon formation 16-fold in comparison with control; as to the antibody production - it was completely abolished. Hydrocortiosone (100 mg/kg) also diminished the interferon production 16-fold, but had no effect on the production of antibodies against the virus. The effect of hydrocortisone on the antiviral immunity was similar to that of the antilymphocytic serum, whereas the action of actinomycin-D resembled the effect of the X-ray irradiation or imuran. The data obtained were consistent with the suggestion on the heterogeneity of cells, participating in the interferon production in the organism.     

The effect of myelopid on antibody formation in gamma-irradiated animals

The effect of a new immunocorrecting preparation, Myelopid, on the antibody-forming cell content of mouse spleen after gamma-irradiation (1-3 Gy) has been investigated. The preparation administered after immunization of mice with sheep erythrocytes increases the number of antibody-forming cells in the spleen, the effect being a function of radiation dose and time interval between the exposure and immunization. The preparation is ineffective when delivered after irradiation, but prior to immunization.     

Effect of stromal fibroblasts on antibody formation in cultures deficient in A-cells]

Stromal fibroblasts from the monolayer cultures of the rabbit thymus, spleen, and bone marrow when added to suspension cultures of non-adherent rabbit spleen cells had a significant effect on the response of the plaque-forming cells (PFC). Thymus-derived stromal fibroblasts caused an increase in the number of PFC, and bone marrow stromal fibroblasts suppressed the antibody formation in these cultures. Spleen-derived stromal fibroblasts influenced the PFC response similarly to adherent cells. Thymus-derived stromal fibroblasts irradiated by 5000 R influenced the PFC response in the same way as non-irradiated cells. The action of stromal fibroblasts on the antibody formation in the cultures depended on their attachment to the culture flask surface.     

Metabolic features of the liver and spleen and antibody formation in animals following hyperimmunization with viral antigens]

Hyperimmunization with the tick encephalitis and Western horse encephalomyelitis viruses reproduced in the brain of albino mice, intensified the protein synthesis in the splenic tissue during the productive phase of the immunogenesis (the 7th day). An accumalation of protein, activation of aniuno-acyl-t-RNA-ligases, a reduction of the concehtration of some amino acids was noted, An analogous reaction was distinct in the tissue of the liver only when an intact brain suspension was used as an antigen. Formation of specific antibodies coursed more intensively after the administration of a more pathogenic virusof Western equine encephalomyelitis.