title: In vivo treatment with a monoclonal chimeric anti-CD4 antibody results in prolonged depletion of circulating CD4+ cells in chimpanzees.
abstract: Chimeric M-T412 (cM-T412), an anti-CD4 antibody, was tolerated in chimpanzees at a dosage of 5 mg/kg per day for up to 7 consecutive days, or 5 mg/kg per dose, twice weekly for 4 weeks. All cM-T412-treated chimpanzees showed a prolonged CD4-cell depression. Weak chimpanzee antibody responses to chimeric M-T412 were observed. One of the chimpanzees on the biweekly dosage regimen exhibited a hypersensitivity reaction immediately after receiving its seventh dose. Following supportive treatment, the animal recovered and remained asymptomatic during the non-treatment observation period. The hypersensitivity reaction was not an unexpected response considering the animal received repeated intermittent i.v. administration of a foreign protein. This animal also showed a chimpanzee antibody response to chimeric M-T412 after the seventh dose. Chimeric M-T412 also induced an anti-cM-T412 response in some of the other animals. The level of this response was lower than the anti-mouse responses observed in animals treated with murine anti-CD4. Moreover, the anti-cM-T412 response was mainly directed to idiotypic determinants. The decrease in CD4+ cells observed for all chimeric M-T412-treated chimpanzees is an expected effect of the anti-CD4 antibody. The duration of this CD4+ cell decrease is, however, much longer than observed for other CD4-specific MoAbs described. No selective loss of either memory or naive CD4+ cells was observed after either the single, 7-day or twice-weekly treatments. The CD4+ cell depression was reversible, although individual variation in time to recovery was observed. Therefore, cM-T412 could be a good candidate for clinical use in autoimmune conditions.
authors.affiliation: Centocor Malvern, PA.
authors.forename: M
authors.initials: M
authors.lastname: Jonker
authors.forename: W
authors.initials: W
authors.lastname: Slingerland
authors.forename: G
authors.initials: G
authors.lastname: Treacy
authors.forename: P
authors.initials: P
authors.lastname: van Eerd
authors.forename: K Y
authors.initials: KY
authors.lastname: Pak
authors.forename: E
authors.initials: E
authors.lastname: Wilson
authors.forename: S
authors.initials: S
authors.lastname: Tam
authors.forename: K
authors.initials: K
authors.lastname: Bakker
authors.forename: A F
authors.initials: AF
authors.lastname: Lobuglio
authors.forename: P
authors.initials: P
authors.lastname: Rieber
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000917:Antibody Formation; D015704:CD4 Antigens / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology*; D006801:Humans; D007111:Immunity, Cellular; D007958:Leukocyte Count; D008212:Lymphocyte Depletion; D051379:Mice; D002679:Pan troglodytes; D011993:Recombinant Fusion Proteins / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D011993:Recombinant Fusion Proteins