PHYLOGENY OF LYMPHOCYTE HETEROGENEITY .4. EVIDENCE FOR T-LIKE AND B-LIKE CELLS IN REPTILES

Peripheral blood lymphocytes from the Florida alligator were separated into at least two subpopulations based upon surface markers and mitogen responsiveness. Fractionation on glasswool columns yielded two subpopulations, a nonadherent one responsive in vitro to PHA and Con A but not to LPS, and an adherent one responsive to LPS (and to PHA). Depletion of cells bearing surface immunoglobulin determinants (by complement-mediated cytotoxicity and by anti-immunoglobulin affinity columns) ablated the responsiveness to LPS (and PWM) but not to PHA. LPS, but not PHA, induced a subpopulation of alligator lymphocytes to differentiate into immunoglobulin producing cells. These data, and other related studies, indicate the Florida alligator likely has T and B cells akin to those of mammals and birds. © 1979 Pergamon Press Ltd. All rights reserved.