The CD34 antigen is present on 1-4% of human marrow cells including virtually all hematopoietic progenitors detected by in vitro assays. Since the anti-CD34 monoclonal antibody 12-8 reacts with a similar marrow population in baboons, it was possible to test whether this antigen is expressed by stem cells responsible for hematopoietic reconstitution in vivo. CD34+ cells were enriched from marrows of five baboons using avidin-biotin immunoadsorption. After lethal irradiation, the five animals were given 15-27 X 10(6) autologous marrow cells (3.2-4.4 X 10(6) cells/kg) containing 65-91% CD34+ cells. All animals achieved granulocyte counts greater than 1,000/mm3 and platelet counts greater than 20 X 10(3)/mm3 by 13-24 d posttransplant and subsequently developed normal peripheral blood counts. Two additional animals received 184 and 285 X 10(6) marrow cells/kg depleted of CD34+ cells. One animal died at day 29 without engraftment, while the other had pancytopenia for greater than 100 d posttransplant. The data suggest that stem cells responsible for hematopoietic reconstitution are CD34+.

https://dm5migu4zj3pb.cloudfront.net/manuscripts/113000/113409/JCI88113409.pdf

Antigen CD34+ marrow cells engraft lethally irradiated baboons.

CD14 : cell surface receptor and differentiation marker

The skin immune system (SIS): Distribution and immunophenotype of lymphocyte subpopulations in normal human skin

In the present study a unique antibody (NKI-L16) reacting with the alpha-chain of the human leukocyte function-associated Ag-1 (LFA-1) is described, which stimulates homotypic cell-cell interactions in a manner very similar to 12-O-tetradecanoyl-phorbol-13-acetate (TPA), in contrast to other anti-LFA-1 mAb which inhibit cell aggregation The induction of aggregate formation of EBV-transformed B cells (JY) and CTL clones by TPA or NKI-L16 is not accompanied by an increase in the expression of LFA-1 Nevertheless, this cluster formation is LFA-1 dependent, inasmuch as anti-LFA-1 antibodies, other than NKI-L16, completely abrogate aggregation Simultaneous addition of NKI-L16 and TPA did not result in a further increase of the speed of cluster formation, suggesting that a similar pathway is activated Immunoprecipitation and enzyme digestion studies revealed that NKI-L16 recognizes a unique epitope on the alpha-chain of LFA-1, most likely situated close to the transmembrane segment of the molecule It is hypothesized that NKI-L16 or TPA can cause the LFA-1 molecule to convert from an inactive to an active configuration, thereby permitting binding of LFA-1 to its natural ligand

/pdf/a-monoclonal-antibody-nki-l16-directed-against-a-unique-2nrh96cjwd.pdf

A monoclonal antibody (NKI-L16) directed against a unique epitope on the alpha-chain of human leukocyte function-associated antigen 1 induces homotypic cell-cell interactions.

Absolute numbers of CD3+ T lymphocytes and their subpopulations were determined and statistically evaluated in the lesional skin of psoriasis, atopic dermatitis, nummular dermatitis, pityriasis rosea, and lichen planus. Skin sections were divided into horizontal layers and the numbers of CD3+ T cells as well as CD4+ inducer and CD8+ suppressor-cytotoxic T-cell subsets were counted. In addition, absolute numbers of the two subpopulations of inducer T cells, i.e., "memory" (4B4+ 2H4-) and "naive" (4B4- 2H4+) were evaluated. Unexpectedly, epidermal infiltration by T cells was highest in psoriasis and lowest in atopic dermatitis. In most cases, this exocytosis was dominated by CD8+ suppressor/cytotoxic T lymphocytes, with a minimal epidermal mean CD4/mean CD8 ratio of 0.04 in pityriasis rosea and a maximum of 0.48 in psoriasis. Inducer T cells within the epidermis were almost exclusively of the 4B4+ 2H4- "memory" T-cell subpopulation, whereas 4B4- 2H4+ "naive" T cells were extremely uncommon in lesional epidermis. Similar results were obtained for dermal T cells in all diseases studied, i.e., 4B4- 2H4+ "naive" T cells were relatively rare. Papillary dermis infiltration by T cells was highest in lichen planus where a mean CD4/mean CD8 ratio of 1.10, the minimum in this comparative study, was obtained. The mean CD4/mean CD8 ratio of the papillary infiltrate was highest in atopic dermatitis (4.12). Our results indicate disease-specific and significantly different infiltration patterns of T-lymphocyte subsets in the chronic inflammatory dermatoses investigated.(ABSTRACT TRUNCATED AT 250 WORDS)

A. Bernard

Papers

Leucocyte Typing: Human Leucocyte Differentiation Antigens Detected by Monoclonal Antibodies