Immunological responses of 'nude' mice.

Mice homozygous for the mutation which lack a thymus, were found to have a marked lymphopenia. They had a marked granulocytosis following administration of , but only slight lymphocytosis. Unlike littermates they failed to develop an increased cellularity of lymph nodes draining a local injection of PHA. They had reduced levels of immunoglobulin but produced some antibody to sheep-RBC. They accepted allografts. Cell cooperation experiments suggest that the immunological deficits of mice can be explained by the absence of a thymusderived cell population.