CDw92 is a 70-kDa surface protein broadly expressed on leukocytes and endothelial cells. In this manuscript, we present the molecular cloning of the CDw92 molecule by using a highly efficient retroviral expression cloning system. Sequence analysis of the CDw92 cDNA revealed a length of 2679 bp. The 1959-bp open reading frame encodes a protein of 652 amino acids. Computational analysis of the CDw92 protein sequence indicates 10 transmembrane domains, three potential N-linked glycosylation sites, and an amino acid stretch in the C-terminal region that is related to the immunoreceptor tyrosine-based inhibitory motif. Comparison of the sequence of the CDw92 clone presented in this study with various database entries show that it is a C-terminal variant of human choline transporter-like protein 1, a member of a recently identified family of multitransmembrane surface proteins. Furthermore, we found that CDw92 is stably expressed on monocytes, PBLs, and endothelial cells, as we did not yet find modulation of expression by various stimuli on these cells. In contrast to this factor-independent expression of CDw92, we detected a specific regulation of CDw92 on monocyte-derived dendritic cells (Mo-DCs). Maturation of Mo-DCs by ionomycin or calcium ionophore resulted in down-regulation of CDw92 and incubation of these cells with IL-10 in a specific re-expression. Moreover, targeting of CDw92 on LPS-treated Mo-DCs by CDw92 mAb VIM15b augmented the LPS-induced IL-10 production 2.8-fold. Together, these data suggest a crucial role of the CDw92 protein in the biology and regulation of the function of leukocytes in particular DCs.

Oestrogen receptors (ER) and progesterone receptors (PR) have been reported by several authors in the stromal cells of the human prostate. Controversial results exist on the expression of ER and PR in epithelial cells of the prostate. Some recent publications, in contrast to previous findings, have suggested that these receptors are also present in human prostate cancer cell lines derived from metastatic lesions. The expression of ER and PR in these cell lines has been re‐examined to determine their presence in lymph node metastases from patients who did not receive any kind of endocrine therapy and in distant metastases obtained from patients who failed endocrine treatment. ER and PR expression in LNCaP, PC‐3, and DU‐145 cells was assessed by means of the reverse transcriptase‐polymerase chain reaction, ligand binding assays, and immunohistochemistry. With all the techniques applied, the three cell lines were found to be negative for both ER and PR. Immunohistochemical analyses were performed in four lymph node metastases obtained at radical prostatectomy from patients who did not receive endocrine therapy and in 17 distant metastases obtained at palliative surgery from patients who failed endocrine therapy. All 21 metastases were negative for ER and PR on immunohistochemistry. These results do not support the recently developed concept that receptors for oestrogenic and progestagenic steroids are present in metastases from human prostate cancer. © 1997 John Wiley & Sons, Ltd.

CD93 is a ∼120 kDa O-sialoglycoprotein that within the hematopoietic system is selectively expressed on cells of the myeloid lineage. So far, its primary structure and function were unknown. We used retroviral-expression cloning to isolate the CD93 cDNA. Sequence analysis revealed that CD93 is identical to a protein on human phagocytes termed C1q receptor (C1qRp). C1qRp was shown previously to mediate enhancement of phagocytosis in monocytes and was suggested to be a receptor of C1q and two other structurally related molecules. When studying CD93 transductants and control cells, we found that cells expressing CD93 have enhanced capacity to bind C1q. Furthermore, we show that immature dendritic cells (DC) express CD93/C1qRp, and mature DC, known to have reduced capacity for antigen uptake and to have lost the ability to phagocytose, show weak-to-negative CD93/C1qRp expression.