Immunohistochemical localization of murine alpha 1-pregnancy-associated protein (alpha 1-PAP) in non-pregnant females: a comparative study with human pregnancy-associated alpha 2-glycoprotein (alpha 2-PAG).
A murine pregnancy-associated protein (alpha 1-PAP) was demonstrated by immunoperoxidase (PAP) staining within Ia positive cells in gut-associated lymphoid tissue and intestinal mucosae of normal female MF1 but not C57BL/10 mice. These immunohistochemical findings reflect the differences in serum alpha 1-PAP concentrations between the two strains, being 50-fold higher in the MF1 females. Staining for alpha 1-PAP was also detected within perivascular and periportal hepatocytes of MF1 mice. Using a combined indirect immunoperoxidase (PAP)/direct immunofluorescence procedure, cytoplasmic alpha 1-PAP was demonstrated in a proportion of plasma cells secreting the IgA isotype. In contrast with human pregnancy-associated alpha 2-glycoprotein (alpha 2-PAG) which was observed in the majority of IgA plasma cells within the lamina propria of human gastrointestinal mucosae, on average only 15% of IgA producers in corresponding mouse tissue were positive for alpha 1-PAP. As with the localization of alpha 2-PAG, no other classes of Ig-producing cells stained for alpha 1-PAP. These observations strengthen recent proposals that alpha 1-PAP is a murine analogue of human alpha 2-PAG, a glycoprotein with immunosuppressive properties.
Udagawa
Y
Y
Armstrong
S S
SS
Waites
G T
GT
Bell
S C
SC
Horne
C H
CH
Thomson
A W
AW
D000818:Animals; D003429:Cross Reactions; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D007124:Immunoenzyme Techniques; D007070:Immunoglobulin A / Q000032:analysis; D007413:Intestinal Mucosa / Q000276:immunology / Q000648:ultrastructure; D008099:Liver / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D010950:Plasma Cells / Q000276:immunology / Q000648:ultrastructure; D011257:Pregnancy Proteins / Q000378:metabolism*; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism*
D000949:Histocompatibility Antigens Class II; D007070:Immunoglobulin A; D011257:Pregnancy Proteins; D011266:Pregnancy-Associated Plasma Protein-A