Identification of a human follicular dendritic cell molecule that stimulates germinal center B cell growth.
The initial interaction between B cells and follicular dendritic cells (FDCs) appears to be essential for germinal center (GC) formation. To identify molecules regulating this interaction, we generated FDC-staining monoclonal antibodies (mAbs) and screened them for their ability to block FDC-mediated costimulation of growth and differentiation of CD40-stimulated B cells. Using one of the inhibitory mAbs, 8D6, we expression cloned the cDNA encoding the 8D6 antigen (Ag) from a human FDC line, HK. The 8D6 Ag is a novel protein of 282 amino acids that is expressed abundantly on FDCs. Monolayers of COS cells transiently transfected with the 8D6 Ag cDNA stimulate B cell growth. The mAb 8D6 blocks the costimulatory function completely. The inhibitory activity of the mAb 8D6 was demonstrated to be due to an inhibition of cell cycle progression of CD40 ligand-stimulated GC B cells. In addition, the mAb 8D6 inhibits the growth of a lymphoma of GC origin, L3055, which depends on FDCs or HK cells for its growth. These findings suggest that the primary function of FDCs in the GC is to stimulate B cell growth. An FDC signal molecule, 8D6 Ag, may be an important molecule to mediate this function.
Li
L
L
Laboratory of Cellular Immunology, Alton Ochsner Medical Foundation, New Orleans, Louisiana 70121, USA.
Zhang
X
X
Kovacic
S
S
Long
A J
AJ
Bourque
K
K
Wood
C R
CR
Choi
Y S
YS
D000818:Animals; D019138:Antibodies, Blocking / Q000494:pharmacology / Q000502:physiology; D000911:Antibodies, Monoclonal / Q000096:biosynthesis; D000918:Antibody Specificity; D000943:Antigens, Differentiation / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology; D002450:Cell Communication / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D002460:Cell Line; D002648:Child; D002675:Child, Preschool; D003001:Cloning, Molecular; D018920:Coculture Techniques; D018076:DNA, Complementary / Q000302:isolation & purification; D020566:Dendritic Cells, Follicular / Q000737:chemistry* / Q000166:cytology / Q000276:immunology*; D018858:Germinal Center / Q000166:cytology* / Q000276:immunology*; D006131:Growth Inhibitors / Q000276:immunology / Q000494:pharmacology; D006133:Growth Substances / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D006801:Humans; D008223:Lymphoma / Q000276:immunology / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D014066:Palatine Tonsil; D011994:Recombinant Proteins / Q000276:immunology / Q000494:pharmacology; D013194:Staining and Labeling; D014407:Tumor Cells, Cultured
D019138:Antibodies, Blocking; D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D018076:DNA, Complementary; D006131:Growth Inhibitors; D006133:Growth Substances; D011994:Recombinant Proteins