Primary immune responses of selected small mammal species to heterologous erythrocytes

Abstract

1. 1. We surveyed the primary humoral immune responsiveness of six small mammal species ( Peromyscus leucopus, Microtus pinetorum, Perognathus hispidus, Neotoma floridana, Onychomys leucogaster, Mus musculus) collected from wild populations in central Oklahoma using sheep red blood cells (SRBC) as the immunogen and a splenic plaque-forming cell (PFC) assay. 2. 2. Individuals within each wild species examined produced antibodies to a single intraperitoneal injection of SRBC, however, considerable interspecific and intraspecific variation in responsiveness was indicated. 3. 3. Overall, primary immune responsiveness varied from 0 to 5013 PFC/10 6 cells. Spleen weights, total splenic nucleated cell yields, PFC/spleen, PFC/mg spleen, and PFC/10 6 cells were significantly different among species. 4. 4. Mean cell yield in 0M. pinetorum was greater than in P. leucopus and CD-1 laboratory mice (included as positive controls). Number of PFC/10 60 cells was greater in CD-1 laboratory mice than P. hispidus and P. leucopus. The coefficient of variation for PFC/10 6 cells in CD-1 laboratory mice was 38% compared to 109, 129, and 56% for M. pinetorum, P. hispidus, and P. leucopus, respectively. 5. 5. Interspecific and intraspecific differences among wild species may be a reflection of disparate life histories and other environmental selection pressures.