DEEP WORK

TROGOCYTOSISTrogocytosis, a form of cell-to-cell interaction widely existing in a species or between different species, involves one cell contacting and quickly “biting” another cell. This interaction was first described in 1970 as part of the process of parasites attacking and killing host cells (1). In 2002,it was given its name from the ancient Greek word “trogo”, which means “nibbling” to de..

IntroductionThe defence system of vertebrates uses sophisticated microbial recognition patterns as a defence mechanism against microbial invasion. On the other hand, pathogens exerts their own invasion and pathogenesis mechanism that are (in most cases) capable of overcoming host defence mechanism, and subsequently establishing infection. The immune defence mechanism including the recognition sy..

INTRODUCTIONThe group of bacterial protein toxins termed pore-forming toxins (PFT) belongs to the family of toxins called membrane-damaging toxins (MDT) which possess the ability to damage or disrupt the integrity of the plasma membrane of various eukaryotic cells (impairment of osmotic balance) reflected by cell swelling and subsequently cell lysis (Bhakdi and Tranum-Jensen 1988; Menestrina and..

INTRODUCTIONBacterial infections are a leading cause of morbidity and mortality worldwide, and bacteria can cause infections in nearly all host tissues. Furthermore, health care-associated urinary tract infections, pneumonia, skin and soft tissue infections, invasive bloodstream infections, and surgical-wound infections are increasingly common (1, 2). The usual method of treating bacterial infec..

Toll-like receptors (TLRs) are of interest to immunologists because of their front-line role in the initiation of innate immunity against invading pathogens1 . The signalling pathways activated by different TLRs have therefore been the focus of much research. TLR signalling involves a family of five adaptor proteins, which couple to downstream protein kinases that ultimately lead to the activati..

INTRODUCTIONThe innate immune system is the first line of host defense that induces immediate, non-specific immune responses against pathogens (1). Inflammation is part of the innate immune system and is initiated when the innate immune system recognizes invading pathogens or molecules from tissue injury through pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs) and inflamm..

VIRUSESViruses enter the host cell to hijack the machinery necessary for viral replication. Viral PAMPs can trigger innate immune responses either on the host cell surface, within the endosome, or in the cytoplasm.  Emerging evidence also suggests that innate immune detection might occur in the nucleus. Inflammasome sensors are activated in response to both DNA and RNA viruses, ensuring efficien..

\ GENERAL OVERVIEW OF INFLAMMASOME SENSING AND SIGNALING  Several cytoplasmic innate immune sensors form inflammasome complexes in response to PAMPs and DAMPs, including AIM2, NAIP, NLRC4, NLRP1, NLRP3, Pyrin, and caspase-11 (Fig. 1); further, mouse NLRP6, NLRP9b, and NLRP12 and human NLRP2, NLRP7, and IFN-inducible protein 16 (IFI16) have also been proposed to activate caspase-1 (5), although t..

TLR Signaling PathwaysRecognition of PAMPs by TLRs leads to transcriptional upregulation of distinct genes, depending on the TLRs and cell types involved (Figure 1). The difference in the signaling cascades activated by the individual TLRs can be partly explained by the TIR domain-containing adaptor molecules recruited to TLRs (Akira et al., 2006). There are five TIR domain-containing adaptors i..

TLRs and Their LigandsThe TLR family is one of the best-characterized PRR families and is responsible for sensing invading pathogens outside of the cell and in intracellular endosomes and lysosomes (Akira et al., 2006). TLRs are characterized by N-terminal leucine-rich repeats (LRRs) and a transmembrane region followed by a cytoplasmic Toll/IL-1R homology (TIR) domain. Ten TLRs have been identif..