The Production of Lymphocytotoxic Antisera of Narrowed Specificity by Selective Adsorption and Immunization*

Alloantigens defined by cytotoxic isoantisera prepared against peripheral rabbit lymphocytes

Seven lymphocytotoxic antisera were produced in rabbits by means of isoimmunization with purified peripheral lymphocytes. The phenotypic profile of the defined lymphocyte antigens was determined in a panel of 97 rabbits. The results indicated the existence of at least two major antigenic determinants. Further typing and cross-absorptions were performed with several of the lymphocytotoxic antisera in order to demonstrate monospecificity. The anti-3 antiserum was used to determine the distribution of the respective antigens in various rabbit organs. The highest concentration of the alloantigen was contained in the spleen, followed in descending order by the lymph nodes, lung, skin, kidney, heart and liver. Fat and red blood cells (rbc) contained no detectable antigen. A two-stage physical adherence column method was used to separate T-derived from B-derived lymphocytes and each fraction was tested for the alloantigen. Alloantigen was detected on both cell types. The fact that the anti-3 antiserum never killed more than 30% of the cells suggests that it could define a subpopulation of lymphocytes.

A new alloantigenic system on human lymphocytes

Certain otherwise well-definedHL-Atyping sera contain extra antibodies which do not appear to be closely related to known HL-A specificites and which react in the cytotoxic test with chronic lymphaticleukemia lymphocytes but not with normal lymphocytes. Despite nonreactivity in thecytotoxic test, absorption studies show that the antigenic factors are well represented onnormal lymphocytes. Based on cross-absorption experiments using both normal andleukemic cells, followed by back-testing with the cytotoxic test against a leukemiccell panel, evidence is presented suggesting the existence of a complex, probablymultiple allelic system on human lymphoid cells which appears distinct from the, HL-Asystem, and is definable by serologic techniques.