to interact with other molecules as well namely CD160 and tumor necrosis factor superfamily member 14 (TNFSF14) also known as LIGHT. Interaction of HVEM and CD160 is inhibitory but interaction with LIGHT is stimulatory. Therefore, HVEM can also induce both stimulation and inhibition. Taken together, it seems that the molecules CD160, BTLA, LIGHT and HVEM form a kind of regulatory network. T cell Both BTLA and HVEM are expressed on naive T cells. This colocalization on a single cell allows them to interact in a cis manner (on the same cell). This interaction is important in immunological tolerance as shown by the fact that BTLA mouse knockdown is unable to develop tolerance to high doses of ovalbumin. Furthermore, the knockdown also proves that BTLA is dispensable for T cell development as no abnormalities were detected in T cells development. When a T cell is fully activated HVEM is internalized and this allows BTLA to interact in a trans manner (with molecules on other cells). This enables other cells who express HVEM to regulate activated T cells. Treg cells express HVEM and are able to facilitate immune suppression through interaction with BTLA. Furthermore, the blockage of BTLA together with PD-1 can help reverting the state of exhaustion which further proves the importance of BTLA as an inhibitory molecule. However, in some cases interaction of BTLA and HVEM can have an opposite effect. For instance, in the case of infection with vaccinia virus BTLA and HVEM interaction promotes survival of CD8+ T cells and production of memory cells. B cell B cell's expression of BTLA is less studied than T cell's but it is clear that peripheral B cells express a high amount of BTLA whereas in bone marrow B cell precursors express a lower amount of BTLA. BTLA has been connected with suppressory function in B cells and its expression is not necessary for B cell development just like in T cells. However, a lower expression of BTLA on B cells in elderly is implied in a less potent response to the influenza vaccine. DC BTLA can also be found on DCs, with mature DCs having a higher expression of BTLA and immature DCs a lower one. Just like in T cells and B cells, most results show that BTLA and HVEM interaction suppresses the maturation of DCs. Clinical significance Tumors In many cases BTLA expression is connected with unfavourable outcomes