Impact on T-cell depletion and CD34+ cell recovery using humanised CD52 monoclonal antibody (CAMPATH-1H) in BM and PSBC collections; comparison with CAMPATH-1M and CAMPATH-1G.
BACKGROUND
Ex vivo T-cell depletion of allogeneic BM (BM) grafts can effectively reduce graft versus host disease (GvHD) and may also apply to transplantation of allogeneic peripheral blood stem cell (PBSC) transplants.


METHODS
Here we have evaluated T-cell depletion and progenitor cell recovery by antibody-mediated cells lysis using three CD52 monoclonal antibodies (MAbs) at different concentrations and cell densities.


RESULTS
CAMPATH-1M was superior to CAMPATH-1H for T-cell depletion of BM samples. Treatment with CAMPATH-1M resulted in up to 2.55 log depletion of CD3+ cells, with recoveries of >or=45% CD34+ cells, >or=67% CFU-GM and >or=65% BFU-E. CAMPATH-1H treatment resulted in up to 1.64 log depletion of CD3+ cells and similar recoveries of CD34+ cells, CFU-GM and BFU-E as seen with CAMPATH-1M. Depletion of CD19+ cells was similar to that observed for CD3+ cells while natural killer (NK) cells were relatively spared compared with the T and B cell populations. Log depletions of T cells from PBSC, as determined by immunofluorescence studies and limiting dilution analyses, were similar using CAMPATH-1M, -1H, and -1G. There were also no differences in the depletion of CD19+ cells or NK cells using the three MAbs. Similar results were obtained for recoveries of CD34+ cells, CFU-GM and BFU-E using all three MAbs, although the recovery of CD34+ cells using the highest concentration of MAbs was significantly greater in CAMPATH-1H treated samples. Increasing the number of PBSC treated with CAMPATH-1H and -1M had no effect on the log depletion of T, B or NK cells and there were no major differences in the log depletions achieved with CAMPATH-1H or -1M. Likewise, the higher PBSC density had no effect on the recoveries of CD34+ cells or committed progenitors and once again CAMPATH-1H gave similar recoveries to those obtained using CAMPATH-1M.


CONCLUSIONS
Although CAMPATH-1M resulted in greater ex vivo T-cell depletion of BM than CAMPATH-1H, in all other respects, the humanised CAMPATH-1H was just as effective as CAMPATH-1M and -1G.
Williams
R J
RJ
Stem Cell Laboratories, Bristol Institute for Transfusion Sciences, Bristol, UK.
Clarke
E
E
Blair
A
A
Evely
R
R
Hale
G
G
Waldmann
H
H
Brookes
S
S
Pamphilon
D H
DH
D000074323:Alemtuzumab; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D061067:Antibodies, Monoclonal, Humanized; D000912:Antibodies, Neoplasm / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology*; D018941:Antigens, CD19 / Q000378:metabolism; D018952:Antigens, CD34 / Q000378:metabolism*; D000951:Antigens, Neoplasm / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology; D001854:Bone Marrow Cells / Q000166:cytology; D016465:Bone Marrow Purging / Q000379:methods; D000074301:CD52 Antigen; D019002:CD56 Antigen / Q000378:metabolism; D006023:Glycoproteins / Q000276:immunology*; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology; D018655:Lymphocyte Count; D051381:Rats; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology*
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000912:Antibodies, Neoplasm; D015703:Antigens, CD; D018941:Antigens, CD19; D018952:Antigens, CD34; D000951:Antigens, Neoplasm; D000074301:CD52 Antigen; C000613862:CD52 protein, human; D019002:CD56 Antigen; C000613864:Cd52 protein, rat; D006023:Glycoproteins; D000074323:Alemtuzumab