Strain differences in lung granuloma formation in response to a BCG cell-wall vaccine in mice. Failure of antigen presentation by low-responder macrophages.

C57BL/6 (B6) mice are high responders whereas C3H/He (C3H) mice are low responders of lung granuloma response to a BCG cell-wall vaccine (BCG CW). Studies with allogeneic bone-marrow chimaeras and tetraparental bone-marrow chimaeras demonstrated clearly that the response is dependent on the cells derived from B6 bone marrow. Cell transfer experiments on these chimaeric mice as well as on T cell-depleted mice indicated that macrophages of C3H origin were responsible for the low responsiveness observed. Alveolar macrophages collected from tetraparental bone-marrow chimaeras which had received intravenously BCG CW 4 weeks before showed the same H-2b/H-2k ratio as that of spleen lymphocytes, thus it was proved that efferent phase of lung granuloma response was not impaired in C3H mice. In addition, C3H mice did produce extensive lung granuloma when BCG CW was first injected subcutaneously and rechallenged intravenously. These results strongly suggest that impairment of antigen presentation, when BCG CW was injected intravenously, caused reduced lung granuloma response in C3H mice.