Functional characterization of primary alloreactive human T-lymphocytes

Functional characterization of primary alloreactive human T-lymphocytes

Abstracts 267 FUNCTIONAL CHARACTEI{IZATION OF PRIMARY ALLOREACTIVF HUMAN T-LYMPHOCYTES. Kornbluth, J. and Dupont, B. Sloan-Kettering Institute, New ...

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Abstracts

267

FUNCTIONAL CHARACTEI{IZATION OF PRIMARY ALLOREACTIVF HUMAN T-LYMPHOCYTES. Kornbluth, J. and Dupont, B. Sloan-Kettering Institute, New York, N.Y. 1002[ Human peripheral blood lymphocytes are activated to proliferate and form colonzes in agarose after brief exposure (24 hours) to allogeneic lymphocytes in liquid culture. Colony development is independent of cell contact and exogenously supplied growth factors. The colonies are composed of T cells which form E-rosettes with sheep erythrocytes and do not express surface Ig. Pooled colonies derived from 24 hour allogeneic stimulation of HLA-D homozygous lymphocytes (HTCs) express the appropriate DR antigens, as m e a s u r e d by complement-mediated cytotoxicity and absorption. Some alloantisera give extra reactions with HTC colony cells (ex. Lewandowski DRwl) that have not been previously detected on B cells and resting T cells suggesting that these sera may also contain antibodies against antigens expressed only on activated T cells. Single colonies removed from agarose undergo extensive proliferation (20-30 generations) in liquid culture with the aid of T cell growth factor provided by conditioned medium (CM). The majority of these T-lymphocyte "clones" tested display specific cytolytic effector function, indicating that within 24 hours ef exposure to alloantigen, responder lymphocytes that subsequently form colonies in agarose are committed to antigen-specific cytotoxic activity; memory for the priming alloantigens is retained after months of culture in the absence of antigen. This demonstrates that primary alloreactive human T-lymphocytes express HLA-DRw antigens and are capable of antigen-specific cytotoxic function.

MECHANISM OF HTC TYPING I. ABSENCE OF SUPPRESSION. P. Lamb, R.J. Hartzman. Lombardi Cancer Center. Immunologic Oncology Division, Georgetown University School of Medicine, Washington, DC 20007 and the Naval Medical Research Institute, Bethesda, MD 20014. In our laboratory there have been several examples of HLA-D heterozygous cells which have acted like HTC's. There are several possible explanations for this phenomenon. First, the single HLA-D specificity difference between the responder and stimulator is inadequate to produce strong stimulation. Second, the stimulator's two HLA-D types have many determinates in common (cross reactive). Finally, the shared antigehs on the stimul~tor and respDnder cells cause suppression. To test this third hfpothesis a 3 cell MLC was performed with: a Dw2 re,ponder cell; an irradiated homozygous Dw2 cell, A; and an irradiated stimulator, B, which shared no common HLA-D specificity with the other two cells. If HTC