Germinal center T cells exhibit properties of memory helper T cells.
Potential roles of germinal center (GC) T cells in immune memory were investigated by examining T cells in GCs lymph nodes (LNs) following immunization with myelin basic protein (MBP). MBP preferentially stimulates T cells expressing the V beta 8 TCR family in B10.PL mice. By staining lymph nodes with peanut agglutinin, GCs were first identified 8 days after immunization and could still be detected 50 days later. When T cells within GCs were examined at Day 8, the majority (> 90%) were CD45RB-negative and a large percentage (20%) had already proliferated several days before as determined by bromodeoxyuridine (BrdU) incorporation. When BrdU+ V beta 8+ cells were examined in various areas of LNs 3 and 8 weeks after immunization, BrdU+ V beta 8+ cells were approximately fourfold more frequent in GCs than other areas of LNs. When GCs were examined for IL-4 mRNA+ cells using an in situ hybridization method, only 0.01% of GC cells expressed IL-4 mRNA, corresponding to about 1% of GC T cells. Shortly following restimulation with MBP, the frequency of cells expressing IL-4 mRNA increased fivefold. Taken together, these findings indicate that GC T cells possess characteristics associated with memory T cells.
Kelly
K A
KA
Division of Laboratory Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Bucy
R P
RP
Nahm
M H
MH
D000818:Animals; D000939:Epitopes; D005260:Female; D007114:Immunization; D007156:Immunologic Memory / Q000276:immunology*; D015847:Interleukin-4 / Q000096:biosynthesis* / Q000235:genetics*; D017493:Leukocyte Common Antigens / Q000032:analysis; D008198:Lymph Nodes / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D004676:Myelin Basic Protein / Q000276:immunology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D000939:Epitopes; D004676:Myelin Basic Protein; D012333:RNA, Messenger; D015847:Interleukin-4; D017493:Leukocyte Common Antigens