Diminished expression of cell-surface complement regulatory proteins in HIV-infected children and with HIV infection of peripheral blood mononuclear cells in vitro.

Experimental data have established that HIV-infected lymphocytes activate the complement system. However, because mammalian lymphocytes possess a series of cell-surface complement regulators that inhibit amplification on autologous cells, complement-mediated destruction of host cells is usually inhibited. These studies were performed to examine whether alterations in the cell-surface complement regulatory proteins decay-accelerating factor (DAF, CD55) and membrane cofactor protein (MCP, CD46) may occur during HIV infection in vitro or in vivo. The physiologic significance of these alterations were assessed by radiolabeled chromium release experiments. We show that MCP fluorescent intensity is significantly lessened in HIV-infected children and that DAF intensity is similarly lessened in infected children with advanced disease. These findings could be duplicated with HIV infection of peripheral blood mononuclear cells in vitro.

Effects of coupled tumor specific antigens (CTSA) on the growth of transplanted tumors in C3 H/HEJ mice.

The effects of coupled tumor specific antigens (CTSA) on the suppression of tumor growth in inbred mice were investigated. Seventy six week old C3H/HEJ female mice were used in the experiment. They were divided into seven groups; each group consisted of ten mice, and each group received a different treatment. The treatments for the different groups were: Human gamma globulin coupled with tumor specific antigens and emulsified in Freund's complete adjuvant (group I); Tumor specific antigens emulsified in Freund's complete adjuvant (group II); Freund's complete adjuvant (group III); Tumor specific antigens (group IV); Human gamma globulin (group V); Groups VI and VII were untreated. Animals in groups (I to V) were given two injections per week for two weeks prior to the transplantation of tumor tissue. They were subsequently given sixteen more injections during an eight week period. The sixth group was transplanted with tumor tissue and the seventh group was neither treated nor transplanted with tumor. The proliferation of the tumor tissue in the different animals was monitored by computing tumor volume at weekly intervals. The results showed that animals in group I developed a state of immune resistance against the transplanted tumor. At the conclusion of the experiment, the average tumor volume in this group was six times smaller than the average volume in the untreated group and twelve times smaller than the average volume in the group treated with Freund's complete adjuvant. Varying degrees of suppression were also noted in the other treated groups.