Eosinophilia. V. Delayed hypersensitivity, blood and bone marrow eosinophilia, induced in normal guinea-pigs by adoptive transfer of lymphocytes from syngeneic donors.

Dinitrochlorobenzene (DNCB) induced delayed hypersensitivity but no eosinophilia in guinea-pigs from two colonies. Citraconic anhydride (CA) induced delayed hypersensitivity and eosinophilia of the blood and bone marrow, and sites of skin tests were also infiltrated by eosinophils. In adoptive transfer of lymphocytes separated from peritoneal exudate cells of strain XIII-sensitized donors, lymphocytes from DNCB-sensitized guinea-pigs transferred antigen-specific delayed hypersensitivity; lymphocytes from CA-sensitized guinea-pigs transferred delayed hypersensitivity, and induced eosinophilia of the blood and bone marrow of the recipients. Treatment of the lymphocytes before transfer with antilymphocyte (thymocyte) globulin or puromycin suppressed the manifestations in the recipients; normal globulin did not. Active sensitization with DNCB induced formation of small amounts, and with CA larger amounts of anaphylactic antibody. Sera from the actively sensitized animals elicited no significant eosinophilia of blood or bone marrow in one group of recipients. Passive anaphylaxis elicited a transient eosinophilia of the blood, but not of the bone marrow. It is postulated that T-helper cells interact with B-lymphocyte precursors, particularly IgE B cells, to stimulate eosinopoeisis. This results in a reserve of mature eosinophils that may be released in any subsequent anaphylactic event.