Interferon-gamma receptor beta chain (IFNgammaR2), also known as IFNGR2, belongs to the type II cytokine receptor family, whose deficiency is a cause of autosomal recessive mendelian susceptibility to mycobacterial disease (MSMD), also known as familial disseminated atypical mycobacterial infection. This accessory factor is an integral part of the IFN-gamma signal transduction pathway and is likely to interact with GAF, JAK1, and/or JAK2. IFNGR2 is a component of the IFNgamma receptor complex along with the IFNgammaR alpha chain (IFNGR1) and is a new Bax suppressor. The C-terminal fragment (cytoplasmic domain) of IFNgammaR2 is expressed in human cancer cell lines of megakaryocytic cancer (DAMI), breast cancer (MDA-MD-468), and prostate cancer (PC3 cells). The Th1 cytokine IFNgamma, acting through its heterodimeric receptors, IFNgammaR1 and IFNgammaR2, in the induction/proliferation of Th1 cells, might suppress the Th2 responses that may underlie atopic asthma. IFNGR2 has always been seen as a key mechanism for shielding T lymphocytes from the antiproliferative effects of the IFNgamma-signal transducer and activator of the transcription 1 (STAT1) pathway.