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Science behind virus-specific T cells

Human leukocyte antigens (HLAs) play an important role in the way the immune system works. HLA is the human body’s version of the major histocompatibility complex (MHC). HLA proteins are inherited from your parents and make up your individual HLA type, or immune profile. One of the important functions of HLA protein is that they present disease-related antigens to T cells of the immune system. Each T cell has a specific target antigen it is able to recognize when presented by (i.e. connected to) an HLA protein. The HLA protein through which a T cell recognizes its target antigen and eliminates a diseased cell is known as its HLA restriction.

Atara’s off-the-shelf, allogeneic T-cell library is designed to be composed of Epstein-Barr virus (EBV)-specific, fully HLA-characterized T cells across a wide range of HLA restrictions:

  1. The EBV-specific T cells selectively identify the EBV antigen-expressing cells displaying the same HLA restriction. The T cell receptor (TCR) that is EBV-specific recognizes the diseased cell in an HLA-restricted manner and becomes activated.
  2. The EBV-specific T cells are activated and expand in number to attack the diseased cells. Once the EBV-specific T cells no longer encounter the target antigen, proliferation of the T cells stop and their numbers recede.