CA IX is a tumour-associated carbonic anhydrase with proposed roles in pH modulation and intercellular communication. Its distribution was examined in normal, benign and malignant breast tissues and compared with expression of breast tumour markers including oestrogen receptor, c-erbB2, c-erbB3 and CD44. Tissue specimens were analysed using immunohistochemistry and/or reverse transcriptase-polymerase chain reaction (RT-PCR). CA IX was detected by IHC in 12/26 (46%) malignant tissues, 4/36 (11%) benign lesions, but not in 10 normal breasts. Staining was mostly confined to plasma membranes of abnormal epithelial cells, but in five cases was found in adjacent stroma. Semi-quantitative RT-PCR detected CA9 mRNA in 25/39 (64%) malignant tumours, 11/33 (33%) benign lesions, but in none of three normal breasts. Comparative RT-PCR analysis of malignant tissues revealed a relationship between CA9 positivity and c-erbB2 overexpression (p=0.05). Moreover, CA9-positive specimens displayed a significantly higher median level of c-erbB2 than CA9-negative ones (p=0.02). No significant association was found with the other markers. The results of this study support the possible importance of CA IX for breast carcinogenesis and suggest its potential use as a breast tumour marker.
Four monoclonal antibodies (mAbs) recognizing distinct antigenic sites on the HA2 glycopolypeptide of influenza virus A/Dunedin/4/73 (H3N2) have been tested for in vivo protection. When applied intravenously before infection, three of them increased the survival of BALB/c mice infected with 1 LD 50 homologous virus. The protection resulted simultaneously in 2 days earlier clearance of virus from the lungs. These three antibodies inhibited the fusion activity of virus in previous in vitro experiments. One of them, specific to N-terminal aa 1-38 of the HA2 glycopolypeptide, was also tested for protection against the heterologous virus A/Mississippi/1/85 (H3N2). Protection similar to that against the homologous virus was observed. The fourth mAb, without fusion-inhibition activity, did not protect mice. It is concluded that antibodies specific to the antigenically conserved HA2 glycopolypeptide that exhibit fusion-inhibition activity can contribute to the protection of infected mice and mediate more effective recovery from infection.
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