CD61 is a membrane glycoprotein that
associates with CD41 (aIIb) to form the heterodimeric
complex gpIIb/IIIa (CD41/CD61), predominantly
expressed in platelets and megakariocytes. CD61 or ß3
integrin also associates with av (CD51) to form the
vitronectin receptor, which is expressed in many tissues.
We have used a monoclonal antibody against the porcine
gpIIIa or CD61 (JM2E5) to study the distribution of this
molecule in different normal pig tissues. As in humans,
CD61 was broadly expressed in all tissues examined. In
the kidney, strong expression of CD61 was observed in
epithelial cells from renal tubules. In the testis, CD61
expression was detected in the Leydig cells. However, in
liver, CD61 was weak or not detected.
Many integrins are particularly involved in
tumogenicity and in tumor progression mediating cellcell
interaction. Immunofluorescence experiments using
cultured human tumor HeLa cells showed nuclear and
cytoplasmic staining of mAb JM2E5. Immunohistochemical
analysis of human tumor sections from several
organs showed a heterogeneus distribution in metastatic
cases from colon and breast carcinoma. However, no
staining was found in metastasis from melanom