Abrogation of T cell homing by alloantibody.

Utilizing a dual isotope assay, the effect of passively transferred enhancing alloantibody on the specific accumulation of cytotoxic T cells in murine skin allografts were examined. (C57BL/6 x A/J)F1 (B6AF1) mice hyperimmunized with weekly injections of B10.D2 and B10.BR lymphoid cells served as a source of anti-B10.D2 and anti-B10.BR alloantibody. Intraperitoneal injections of alloantibody in B6AF1 hosts on days 0,2, and 4 significantly prolonged skin allograft survival. Dually skin allografted B6AF1 mice with or without the administration of enhancing alloantibody received differentially labeled (3H/14C) cytotoxic T cells on day 5. On day 7, a "homing index" derived from the comparison of 3H to 14C ratios was calculated for the skin allografts and draining axillary lymph nodes of each mouse. In unenhanced, normal mice significant preferential homing of cytotoxic T cells to skin allografts was demonstrated. However, enhanced mice receiving cytotoxic T cells had significantly dimished homing to skin allografts. Preferential localization of effector cells to the draining axillary lymph nodes was not present in either unenhanced or enhanced mice. These data demonstrate that enhancing alloantibody interferes with the specific accumulation of cytotoxic T cells in skin allografts and may be an important previously undescribed mechanism of immunological enhancement.