Co‐expression of Mac‐1 and p150,95 on CD5⁺ B cells. Structural and functional characterization in a human chronic lymphocytic leukemia

Abstract

The leukocyte adhesion receptors (LAR) Mac-1 and p150,95 were thought to occur only on myeloid cells, but recently, mouse Ly-1+ (CD5+) B and pro-B cells were shown to bind M1/70 monoclonal antibody, an anti-Mac-1 antibody. Using immunoprecipitation, sodium dodecyl sulfate gel electrophoresis, immunofluorescence and flow cytometry, we have studied the expression of LAR in human CD5+ B cells from chronic lymphocytic leukemia (B-CLL) patients. 170,95 kDa Mac-1 and p150,95, as well as 180,95 kDa LFA-1 heterodimers are shown to be co-expressed on CD5+ mu + kappa + B cells from a patient where they retain their known function in homotypic cell-cell adhesion. Therefore, functional Mac-1 and p150,95 LAR are not restricted to myeloid cells.

IFN-gamma signaling in the central nervous system controls the course of experimental autoimmune encephalomyelitis independently of the localization and composition of inflammatory foci

“…CD11b is easily detectable by immunohistochemistry on infiltrating macrophages, dendritic cells and neurtophils along with NK and some CD8+ T cells [36-40]. Microglia strongly express CD11b when activated but do so only faintly when in resting state.…”

Age‐dependent increase of peritoneal B‐1b B cells in SCID mice

“…CD5‐deficient mice have normal numbers of IgM hi peritoneal cavity B cells and normal humoral immunity; the B‐1b subset was not studied in these mutants 41 . The integrin β 2 Mac‐1 (CD11b/CD18, CR3) is expressed at varying levels on granulocytes, macrophages, dendritic cells and natural killer cells as well as B‐1 cells, and binds both C3bi and intercellular adhesion molecule‐1 (CD54) 42 . CD11b‐deficient mice have reduced function in, and numbers of, peritoneal cavity resident mast cells 43 .…”

Role of CR3 (CD11b/CD18) and CR4 (CD11c/CD18) expressed by B lymphocytes of healthy donors and chronic lymphocytic leukaemia patients

“…Among these adhesion receptors, β2 integrins are also expressed by various B cell lymphomas, such as by diffuse large B cell lymphoma, mantle cell lymphoma, Hodgkin's lymphoma, CLL or Burkitt's lymphoma (111). Out of the detected β2 integrins CR3 and CR4 have been shown to be expressed in Hodgkin's lymphoma (112), hairy cell leukaemia (9) and in chronic lymphocytic leukaemia (7)(8)(9)(10)(11)(12)(13)(14).…”

“…CR3 and CR4 are also known to be expressed in various B cell malignancies (7)(8)(9)(10)(11)(12)(13)(14)112),…”

“…These receptors can also be detected on certain subpopulations of B cells or after activation by different stimuli (1)(2)(3)(4)(5)(6). Moreover, these complement receptors have been shown to be expressed in various B cell malignancies such as in chronic lymphocytic leukaemia (CLL) (7)(8)(9)(10)(11)(12)(13)(14). The kinetics of expression and the role of these β2 integrins however, in human B lymphocytes have only scarcely been studied so far.…”