Question

The co-stimulatory molecule _____ on professional antigen-presenting cells binds _____ on the surface of naive T cells. Hint: This is important for strengthening of Tcell/APC interaction and for intracellular signaling

1) DC-SIGN; ICAM-3
2) B7; CD28
3) ICAM-1; LFA-1
4) MHC class II; T-cell receptor
5) MHC class II; CD4

Answer 1

The co-stimulatory molecule B7 on antigen-presenting cells binds to CD28 on naive T cells, important for T cell/APC interaction and activation.

Step-by-step explanation:

The co-stimulatory molecule on professional antigen-presenting cells (APCs) that binds to the surface of naive T cells is B7; it binds to CD28 on naive T cells. This interaction is crucial for the strengthening of T cell/APC interaction and for intracellular signaling, thereby contributing to the activation of T cells. Naive T cells express either CD4 or CD8 molecules, which assist with binding to MHC molecules on APCs, with CD4+ cells binding to MHC class II molecules on professional antigen-presenting cells, such as macrophages, dendritic cells, and B cells.

The interaction between professional antigen-presenting cells (APCs) and naive T cells relies on co-stimulatory molecules, particularly the B7 molecule on APCs binding to the CD28 receptor on naive T cells. This engagement is crucial for fortifying the T cell/APC interaction and initiating intracellular signaling pathways, ultimately contributing to T cell activation. Naive T cells express either CD4 or CD8 molecules, facilitating their interaction with major histocompatibility complex (MHC) molecules on APCs. CD4+ T cells specifically bind to MHC class II molecules present on professional antigen-presenting cells such as macrophages, dendritic cells, and B cells. The coordinated interplay between co-stimulatory molecules and MHC interactions is fundamental for the effective activation of naive T cells, triggering adaptive immune responses essential for the body's defense against pathogens and foreign substances.