Abstract

UNDERSTANDING OF COMPLEX SIGNALING PATHWAYS OF IMMUNE SYSTEM: A REVIEW

Anoop Kumar, D. Sasmal and Neelima Sharma*

ABSTRACT

Cell surface receptors receive the initial signals that activate immune responses. Immune response is very complex process which involves a number of cell types that function as initiators, regulators, and effectors. These cells interact with and cross-regulate each other, and the target cells respond using signal transduction pathways to mediate gene expression. Innate immune responses to pathogens such as bacteria and viruses are triggered by recognition of specific structures of invading pathogens called pathogen-associated molecular patterns (PAMPs) by cellular pattern recognition receptors (PRRs) that are located at plasma membrane or inside cells. Stimulation of different PAMPs activates Toll-like receptor (TLR)-dependent and -independent signaling pathways that lead to activation of transcription factors nuclear factor-κB (NF-κB), interferon regulatory factor 3/7 (IRF3/7) and/or activator protein-1 (AP-1), which collaborate to induce transcription of a large number of downstream genes. In case of Adaptive immune response the signal will be processed MHC antigenic peptide complexes on APCs.This event catalyzes a series of intracellular events resulting in the transcription of genes that drive the differentiation of the T cell.The innate and the adaptive immunity signaling pathways are different, but they usually work together to eliminate pathogen. In this review, we discuss our current understanding of complex signaling pathways of immune system.

Keywords: Toll like receptors; dendritic cells; NFK?; CD markers; T cell.