Human T cells armed with Her2/neu bispecific antibodies divide, are cytotoxic, and secrete cytokines with repeated stimulation.
OBJECTIVE
Cancer immunotherapy has been limited by anergy of patient T cells, inadequate numbers of precursor tumor-specific CTL, and difficulty in producing therapeutic doses of CTL. To overcome these limitations, bispecific antibodies have been used to create artificial antibody receptors that direct polyclonal activated T cells (ATC) to target tumor antigens. Studies reported herein were designed to characterize bispecific antibody-armed ATC functions during multiple rounds of targeted cell stimulation.


METHODS
ATCs were generated from human peripheral blood mononuclear cells (PBMC) by culture with anti-CD3 and interleukin 2 for 14 days and armed with anti-CD3 x anti-Her2 bispecific antibody (Her2Bi). In vitro, Her2Bi-armed ATC were examined for a range of functions after repeated stimulation with the Her2/neu-expressing breast cancer cell line SK-BR-3. PBMC isolated from cancer patients treated with Her2Bi-armed ATC were tested ex vivo for cytotoxicity against SK-BR-3.


RESULTS
In vitro, armed ATC divided, maintained surface Her2Bi, and expressed a range of activities for extended periods of time. Perforin-mediated cytotoxic activity by armed ATC continued for at least 336 hours, and cytokines and chemokines (i.e., IFN-gamma and regulated on activation, normal T-cell expressed and secreted protein [RANTES]) were secreted during successive rounds of stimulation. Furthermore, PBMC isolated from patients over their courses of immunotherapy exhibited significant cytolytic activity against SK-BR-3 as a function of Her2Bi-armed ATC infusions.


CONCLUSIONS
These studies show that armed ATC are specific, durable, and highly functional T-cell populations in vitro. These previously unappreciated broad and long-term functions of armed ATC are encouraging for their therapeutic use in treating cancer.
Grabert
Ryan C
RC
Immunotherapy and Blood and Stem Cell Transplant Programs, Adele R. Decof Cancer Center and Division of Hematology/Oncology, Department of Medicine, Roger Williams Medical Center, 825 Chalkstone Avenue, Providence, RI 02908, USA.
Cousens
Leslie P
LP
Smith
Janelle A
JA
Olson
Sarah
S
Gall
Jonathan
J
Young
Wendy B
WB
Davol
Pamela A
PA
Lum
Lawrence G
LG
D018033:Antibodies, Bispecific / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000276:immunology / Q000628:therapy*; D017252:CD3 Complex / Q000276:immunology*; D045744:Cell Line, Tumor; D018946:Chemokine CCL5 / Q000378:metabolism; D003602:Cytotoxicity, Immunologic; D005260:Female; D006801:Humans; D007167:Immunotherapy; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000276:immunology; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000494:pharmacology; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D018033:Antibodies, Bispecific; D017252:CD3 Complex; D018946:Chemokine CCL5; D007371:Interferon-gamma; D007376:Interleukin-2; D008562:Membrane Glycoproteins; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases