Two populations of guinea pig erythrocyte-rosetting cells in the cat: evidence for their T-helper function in mitogen-induced synthesis of Ig and interleukin-2.
Studies in our laboratory have shown that T-helper (T-H) and T-suppressor (T-S) cells in cat peripheral blood leukocytes (PBL) rosette with guinea pig (GP) and gerbil (G) erythrocytes (E), respectively. Removal of GE-rosetting cells leads to an enhanced (two- to threefold) synthesis of Ig in a pokeweed mitogen (PWM)-driven system as measured by plaque-forming cells (PFC) to protein A-coated sheep RBC, while depletion of GPE-rosetting cells yields a PFC response only 10-15% of the control. Surprisingly, removal of both GE- and GPE-rosetting cells gave a response equivalent to 40-100% of the control PBL. Analysis of the mixed GE/GPE rosette depleted cultures revealed the reappearance of GPE- but not GE-rosetting cells, reaching maximum values within 12-18 hr after in vitro culture. Cultures of control PBL and those following the mixed rosette depletion showed two populations of GPE-rosetting cells; the GPE-1 cells, present on Day 0 before culture, and the GPE-2 cells, those appearing on Day 1. Addition of cycloheximide prevented development of the GPE receptor while colchicine and mitomycin C were without effect. The development of PFC after the mixed GE/GPE rosette depletion was interpreted as being due to the GPE-2 cells functioning as T-H cells in the absence of any T-S (GE-rosetting) cells. This thesis was supported by showing a marked decrease in the PWM-induced Ig response when both the GPE-1 and GPE-2 populations were removed on Day 1. Additional evidence for functional T-H cells in the GPE-rosetting population was obtained by analyzing interleukin-2 (IL-2) production. Removal of the GPE-rosetting cells (GPE-1 and/or GPE-2) from PBL led to a marked decrease in Con A-induced IL-2 synthesis while removal of the GE-rosetting cells yielded a normal or slightly greater than normal response.
Gengozian
N
N
Department of Pediatrics, All Children's Hospital, St. Petersburg, Florida.
Hill
R J
RJ
Good
R A
RA
Day
N K
NK
D000818:Animals; D000917:Antibody Formation; D002415:Cats / Q000097:blood / Q000276:immunology*; D002469:Cell Separation; D003208:Concanavalin A / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000096:biosynthesis*; D008213:Lymphocyte Activation / Q000187:drug effects; D016131:Lymphocyte Subsets / Q000276:immunology; D012397:Rosette Formation; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D007376:Interleukin-2; D003208:Concanavalin A; D003513:Cycloheximide