Immunolocalization of an angiogenic factor (HAF) in normal, inflammatory and tumor tissues

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Abstract
The distribution of a novel human angiogenic factor (HAF) (Schulze Ostoff et al., 1987) has been investlgated on various human cell lines, isolated blood cells as well as in normal, inflammatory and tumor tissues. Localization was performed by using the monoclonal antibody (MAb) 5F4 directed against HAF. It was found that 30% of freshly isolated human monocytes expressed the 5F4 antigen. The number of postitive cells increased to 75–90% on day 4 to 7 upon culture and then decreased. Twenty percent of freshly isolated human lymphocytes also stained positively, whereras graunlocytes and platelets were negative. In cryostat sections of normal human tissue (skin, lung, liver, spleen, placenta) 5F4 is positive with capillary endothelial cells and few macrophages. In inflammatory tissue derived from gingivitis and rheumatoid arthrritis, more macrophages than in normal tissues and less endothelial cell were postitive, In tumor tissues some endothelia cells and a subset of tumor-infiltrating macrophages expressed the antigen. Tumor cells were positive in advanced melanoms, but only occasionlally in stomach carcinomas. We conclude that the angiogenic factor is produced mainly by a subset of inflammatory macrophages which appear to be the principal source of HAF in regenerating or growing tissues.