Development of two manifestations of T-lymphocyte reactivity during tumor growth: altered kinetics associated with elevated growth rates.
Tumor-specific, cell-mediated immune responses (CMI) in mice were measured during the growth of transplantable tumors with the use of lymphocyte-mediated cytotoxicity and the recently developed leukocyte adherence inhibition (LAI) microtest. When both tests were used in parallel to assess CMI, no consistent correlation was found, which suggested that each test was a measure of the activity of a functionally different T-lymphocyte subpopulation. The results of blocking factor (BF) assays with both tests agreed in 78% of the instances; the LAI microtest was much more sensitive for BF determination than lymphocyte cytotoxicity, since blocking serum concentrations as low as 0.25% could demonstrate BF activity in the microstest. In other experiments, the kinetics of development of tumor-specific CMI was followed in normal mice and those under toxic stress; the stressed animals showed depressed humoral and cell-mediated immune responses and enhanced tumor growth rates after the inoculation of tumor cells. In normal mice, a cytotoxic response always appeared in the spleens and regional lymph nodes 3-5 days before an LAI response. Enhanced tumor growth rates in the animals under toxic stress were associated with a reversal in the order in which these two manifestations of T-lymphocyte responsiveness developed; LAI responses always developed before, and often in the complete absence of, cytotoxicity.
D000818:Animals; D001769:Blood; D003601:Cytotoxicity Tests, Immunologic; D007104:Immune Adherence Reaction; D007106:Immune Sera; D007111:Immunity, Cellular; D007700:Kinetics; D008175:Lung Neoplasms / Q000276:immunology; D008545:Melanoma / Q000276:immunology; D051379:Mice; D009374:Neoplasms, Experimental / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D007106:Immune Sera