Alveolar macrophages. V. Comparative studies on the antigen presentation activity of guinea-pig and rat alveolar macrophages.

The addition of syngeneic alveolar macrophages (AM) to mitogen-stimulated lymphocyte cultures from the rat and the guinea-pig resulted in markedly dissimilar effects upon in vitro blastogenesis, guinea-pig AM stimulating the response and rat AM exhibiting strong suppressive activity. The capacity of guinea-pig and rat AM to initiate antigen-specific blastogenesis was also examined. Ovalbumin-immune lymph node cells from guinea-pigs were passed through nylon wool columns to deplete macrophages. This process abolished their capacity to respond to the antigen via blastogenesis. The addition of ovalbumin-pulsed AM to these cultures restored their blastogenic responsiveness, and did so with considerably greater efficiency than was observed employing peritoneal macrophages from the same animals. Identical manoeuvres in the rat again yielded opposite results; the addition of rat AM to syngeneic antigen-stimulated lymphoid cell cultures consistently suppressed blastogenesis, an effect not seen employing peritoneal macrophages from the same species.