The abrogation of TCR-independent interactions with human serum ensures a selective capture of therapeutic virus-specific CD8+ T-cells by multimer technology in Adoptive Immunotherapy.
Multimers are complexes of recombinant MHC-class I molecules conjugated with antigenic immunodominant peptides and labeled with fluorescent molecules or magnetic microbeads that allow the quantification and selection of virus-specific cytotoxic T-cell subpopulations. Specific T-cell receptors recognize the immunodominant peptides and bind to the multimers. Although these complexes are only recognized by CD8(+) T cells with specific T-cell receptors for the particular antigen, it has been observed that multimers can also bind non-specifically to CD8- cells, such as B-cells and monocytes. Using PBMCs from CMV-seropositive healthy donors, we analyze the tendency of Pentamer and Streptamer multimers towards non-specific interactions and describe a method to avoid this unwanted event. We find that a notable proportion of multimer-positive cells are likely to represent cross-contamination by cells lacking a TCR specific for pp65. In addition, we demonstrate that this unspecific interaction can be overcome by the pre-incubation of multimer-stained PBMCs with human AB serum, without altering their capacity to bind specifically to the CD8(+) T cell population of interest. In conclusion, in this study we characterize a novel method to abrogate TCR-independent interactions of multimers to ensure a pure and safe therapeutic product for Adoptive Immunotherapy.
Oncohematology Research Group, Navarrabiomed-Fundación Miguel Servet, Pamplona, Spain.
Lorea
L
Beloki
Miriam
M
Ciáurriz
Cristina
C
Mansilla
Eva
E
Bandrés
Mercedes
M
Rodríguez-Calvillo
Natalia
N
Ramírez
Eduardo
E
Olavarría
D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D003587:Cytomegalovirus / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D016219:Immunotherapy, Adoptive; D007963:Leukocytes, Mononuclear / Q000276:immunology; D010750:Phosphoproteins / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology* / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014763:Viral Matrix Proteins / Q000276:immunology*
D015395:Histocompatibility Antigens Class I; D010750:Phosphoproteins; D011948:Receptors, Antigen, T-Cell; D014763:Viral Matrix Proteins; C464963:pp67 protein, human cytomegalovirus
(Fc-gamma high-affinity receptor I A); (Pentamer); (Streptamer); (T cell receptor); (Tetramer); (β2-microglobulin); CMV-specific CTL; Fcgamma receptor I (FcγRI); FcγRIA; PM; Pentamers; ST; Streptamers; TCR; TM; β2m