Antigen-liposome modification of target cells as a method to alter their susceptibility to lysis by cytotoxic T lymphocytes

A method of liposome modification of cell surfaces to render unsuitable target cells susceptible to lysis by anti-viral cytotoxic T lymphocytes (CTLs) is described. Liposomes containing the hemagglutinin-neuraminidase (HN) and fusion (F) glycoproteins of Sendai virus as well as purified H-2K(k) antigens were capable of binding to the surface of H-2-negative cells and rendering those cells susceptible to lysis by B10·A anti-Sendai virus or anti-H 2K(k) CTLs. The absence from the modifying liposomes of the HN or F proteins or H-2K(k) antigens eliminated the ability of the target cells to be recognized and lysed by either effector cell population. Vesicles containing HN, H-2K(k) molecules, and inactive fusion protein (Fo) were not capable of increasing the susceptibility of H-2-negative target cells to lysis. Liposomes containing inactive fusion protein were similarly unable to render H-2-positive target cells susceptible to lysis by anti-Sendai virus CTLs, suggesting that fusion of the liposomes to the cell surface is a prerequisite to lysis. It did not appear that attachment of liposomes to the cell surface was sufficient for generation of susceptible targets, however, because attachment to the cell surface was observed, as long as the HN glycoprotein was present in the liposomes. These results indicate that purified H-2K(k) glycoproteins are target antigens for anti-H-2(k) CTLs and that B10·A amto-Sendai virus CTLs recognize in an H-2-restricted manner the HN F, or both glycoproteins of Sendai virus in the context of the purified H-2K(k) glycoproteins. This technique of liposome modification of cell surfaces has potential applications in the examination of CTL antigen recognition and immunotherapy of many viral and neoplastic diseases.