Biomedical subjects

K Micklem

Publications and source records attributed to K Micklem.

22 records · Page 2Linked to original sources

PubMed1989

A human macrophage-associated antigen (CD68) detected by six different monoclonal antibodies.

Antibodies grouped together by the Third Workshop on Leucocyte Differentiation Antigens on the basis of pan-macrophage reactivity on tissue sections were analysed in immunoprecipitation experiments. Antibodies Y2/131, EBM11, Ki-M6 and Ki-M7 all precipitated antigens of Mr 110,000 which were shown to be identical by preclearing experiments. In addition a recently produced antibody, KP1, which identifies macrophages in paraffin-embedded tissue, was shown to recognize the same antigen. The antibodies were tested on murine cells transfected with two clones, which had been isolated by screening a cDNA library with antibodies Y1/82A and EBM11. Cells transfected with the longer cDNA clone, coding for a molecule of Mr 110,000, reacted with antibodies Y2/131, EBM11, Y1/82A and Ki-M6, whilst the shorter clone, encoding a molecule of Mr 70,000 gave the same result except that it did not induce expression of the Ki-M6 epitope. KP1 antibody did not recognize any transfectants, possibly because of differences in glycosylation by the transfected cell line compared with human tissue. Five of the six antibodies appear to recognize different epitopes (the sixth, Ki-M7, not having been evaluated in this way). It was concluded that these six antibodies react with a macrophage-associated antigen for which the gene has been cloned. This group of antibodies has recently been designated CD68 by the Fourth Workshop on Human Leucocyte Differentiation Antigens.

Antibodies, Monoclonal↗

PubMed1987

Value of monoclonal anti-CD22 (p135) antibodies for the detection of normal and neoplastic B lymphoid cells.

Two monoclonal antibodies (To15 and 4KB128) specific for the B cell-associated CD22 antigen (135,000 mol wt) are described. On immunoenzymatic analysis of cryostat tissue sections, these antibodies strongly label both mantle zone and germinal center B lymphoid cells in secondary lymphoid follicles (and also scattered extrafollicular lymphoid cells) but are unreactive with other cell types (with the exception of weak reactivity with some epithelioid histiocytes). These reactions differ from those of monoclonal antibodies B1 and B2 (anti-CD20 and CD21) but are similar to those of the pan-B antibody B4 (anti-CD19). One of the anti-CD22 antibodies (To15) has been tested extensively by immunoenzymatic labeling on greater than 350 neoplastic lymphoid and hematological samples. The CD22 antigen was found in tissue sections in most B cell-derived neoplasms, the major exceptions being myeloma (all cases negative) and a small proportion of high-grade lymphoma (6% of cases negative). In cell smears, the antigen could be found on neoplastic cells in most B cell lymphoproliferative disorders, including common acute lymphoblastic leukemia (ALL) (90% positive) and B cell chronic lymphocytic leukemia (CLL) (89% positive). We conclude that anti-CD22 antibodies are of value for identification of human B cell lymphoproliferative disorders (especially when used in conjunction with anti-CD19 antibodies). Previous reports that the CD22 antigen is absent from many B cell neoplasms are probably due to its being expressed within the cytoplasm of immature B cells rather than on their surface.

Antibodies, Monoclonal↗

PubMed1986

A monoclonal antibody recognizing the p150/95 leucocyte differentiation antigen.

A monoclonal antibody KB90 recognizing a molecule containing two polypeptide subunits of 140 and 98 kd is described. Biochemical studies following high pH dissociation of the molecule showed KB90 to bind to an epitope on the 140 kd subunit. The molecule recognized by KB90 appears to correspond to the p150/95 molecule in the family of leucocyte differentiation antigens of which the LFA-1 and Mac-1 molecules are members. Analysis of the immunocytochemical reactivity of KB90 shows that it stains monocytes, tissue macrophages, granulocytes and a small population of lymphocytes. These reactions are clearly distinct from those of the LFA-1 and Mac-1 molecules.

Animals↗

PubMed1985

The generation of active fragments of complement receptor type 2 by trypsin digestion.

B lymphocytes and Raji cells express the complement receptor type 2 (CR2) of 145 kDa which recognises the C3d fragment of C3. When intact cells are treated with trypsin, CR2 is degraded. There is a parallel loss in C3d-mediated rosetting and in proteins which bind to C3d-Sepharose. Initially 97 and then 83 kDa fragments of CR2 are produced which retain C3d binding activity. These fragments are associated with the cell surface and mediate rosetting. Purified 125I-labelled CR2, solubilised in detergent, produces fragments of apparently identical size on treatment with trypsin. The 83 kDa fragment produced by trypsin treatment closely resembles the major C3d binding protein spontaneously released into Raji cell culture medium.

B-Lymphocytes↗