Characterization of rat LECAM-1 (L-selectin) by the use of monoclonal antibodies and evidence for the presence of soluble LECAM-1 in rat sera.
We have characterized the rat LECAM-1 (L-selectin) by the use of newly generated hamster anti-rat LECAM-1 monoclonal antibodies (mAb) (HRL1, HRL2, HRL3, HRL4), with respect to the biochemistry, cellular distribution and function, and developed an ELISA system to detect the soluble form of rat LECAM-1. In the rat, lymphocyte and neutrophil LECAM-1 have apparent molecular masses of 65 and 62 kDa, respectively, and differential glycosylation may account for the molecular heterogeneity. Readily detectable levels of LECAM-1 are expressed on peripheral blood lymphocytes and neutrophils, but not on thymocytes. Lymphocyte LECAM-1 is rapidly shed from the cell surface upon cell activation with PMA, but not with interleukin (IL)-8. In contrast, neutrophil LECAM-1 showed rapid shedding upon stimulation with phorbol 12-myristate 13-acetate (PMA) or IL-8. Concomitantly there is up-regulated expression of Mac-1 in PMA- and IL-8-stimulated neutrophils. Neutrophil rolling in mesenteric venules was significantly inhibited by administration of function-blocking anti-rat LECAM-1 mAb HRL3, but not by non-blocking HRL4, indicating that LECAM-1 plays a significant role in leukocyte rolling. Given that LECAM-1 is rapidly shed from the cell surface, we attempted to develop an ELISA system for detecting LECAM-1 is soluble form, and measured the levels in experimental autoimmune uveitis. The circulating levels of LECAM-1 increased from day 4, which preceded the appearance of clinical signs of uveitis and remained high until uveitis subsided, suggesting that soluble LECAM-1 is potentially a useful parameter to monitor certain types of inflammatory or immune disorders.
Tamatani
T
T
Department of Immunology, The Tokyo Metropolitan Institute of Medical Science, Japan.
Kitamura
F
F
Kuida
K
K
Shirao
M
M
Mochizuki
M
M
Suematsu
M
M
Schmid-Schönbein
G W
GW
Watanabe
K
K
Tsurufuji
S
S
Miyasaka
M
M
D000210:Acute-Phase Reaction / Q000097:blood; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology*; D015815:Cell Adhesion Molecules / Q000032:analysis* / Q000097:blood / Q000276:immunology; D002450:Cell Communication; D006224:Cricetinae; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007249:Inflammation / Q000097:blood; D019041:L-Selectin; D007962:Leukocytes / Q000737:chemistry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011233:Precipitin Tests; D051381:Rats; D011917:Rats, Inbred Lew; D017208:Rats, Wistar
D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; D019041:L-Selectin