CD4, a single chain transmembrane glycoprotein is found on a T cell subset (helper/inducer) representing 45% of peripheral blood lympocytes. It is also present on 80% of thymocytes and at a lower level on monocytes. It is involved in recognition of antigen presented along with MHC class II by APCs. It serves as receptor for HIV. Antibody to CD4 recognizes T-helper cells required for recognition of class II antigens. It reacts with 60% of peripheral blood E rosette-positive (E+) cells while showing negligible reactivity with E+ cells, monocytes, granulocytes, EBV-transformed B cell lines, and mouse splenocytes.
CD4-positive T-cells provide helper funciton in pokeweed mitogen driven B-cell differentiation. Moreover, anti-CD4 selectively blocks the autologus mixed lymphocyte reaction (AMLR) with minimal or no effect on the allogeneic MLR (allo-MLR). Blocking of the autoreactivity occurs when either autologus B-lymphocytes or macrophages are used as stimulators. Specificity closely approximates the binding spectrum of OKT4 and Leu-3 antibodies both of which also recognize 55 to 65% of human peripheral blood T-cells.
Applications
Suitable for use in Flow Cytometry, Radioimmunoprecipitation, and Immunohistochemistry. Other applications have not been tested.
Recommended Dilutions
Immunohistochemistry: 1:4000 (Acetone-fixed frozen sections. Does not stain paraffin embedded tissue sections). Optimal dilutions to be determined by the researcher.
Storage and Stability
May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Aliquots are stable for 12 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
Immunogen
Normal human blood lymphocytes
Form
Supplied as a liquid in PBS, pH 7.5, 0.09% sodium azide.
Purity
Purified by column chromatography.
Specificity
Recognizes and is highly reactive with human CD4 antigen (MW 59kD). Partially blocks binding of monoclonals to Leu-3a. Antibodies do not cross-block with gp129 and do not inhibit HIV induced syncytium formation.