Host defense response

There are various severity of illness scoring systems for sepsis and trauma (R11). Severity scoring can be used, in conjunction with other risk factors, to anticipate and evaluate outcomes, such as hospital mortality rate. The most widely used system is the Acute Physiology, Age, Chronic Health Evaluation II (APACHE II) classification system (K12). The APACHE III was developed to more accurately predict hospital mortality for critically ill hospitalized adults (K13). It provides objective probability estimates for critically ill hospitalized patients treated in intensive care units (ICUs). For critically ill posttrauma patients with sepsis or SIRS, another system for physiologic quantitative classification and severity stratification of the host defense response was described recently (R11). However, this Physiologic State Severity Classification (PSSC) has yet not been applied routinely in ICU setting. 

Loose LD, Mudzinski SP, Silkworth JB. 1981. Influence of dietary polybrominated biphenyl on antibody and host defense responses in mice. Toxicol Appl Pharmacol 59 25-39. 

We have already described that a number of rhizobial LPS mutants are sym-biotically defective because they likely induce an increased defense response by the host and/or are more sensitive to the host defense response. One structural feature of rhizobial LPS that appears to be important is the presence of OPS since its absence appears to result in a more robust plant defense response. We have also suggested (above) that the lack of OPS exposes the anionic COS on the bacterial surface which may make the rhizobial cell more sensitive to antimicrobial cationic peptides. Recent work in our laboratory (Brown, unpublished) has shown that a mutation of R. leguminosarum biovar viciae 3841 which specifically results in the loss of GalA residues from the core increases resistance to cationic peptides. It has also recently been shown that R. etli CE3 mutants in IpxE and IpxF, which are unable to remove the 1 and 4 -phosphates and, therefore have LA with increased anionic character, show increased sensitivity to cationic peptides (Ingram et al., 2010). 

Perotto, S., Brewin, N.J., Kannenberg, E.L. Cytological evidence for a host defense response that reduces cell and tissue invasion in pea nodules by hpopolysaccharide- defective mutants of Rhizobium leguminosarum strain 3841. Mol Plant-Microbe Interact 7 (1994) 99-112. 

IL-12, originally termed cytotoxic lymphocyte maturation factor (514), is a growth factor for CD4+ and CD8+ T-cells and NK cells (515), and has been shown to modulate the cytolytic and proliferative activity of these cells. In vitro, IL-12 is able to direct T-cells to a Thl phenotype, and induces production of IFNy and TNFoc (516). IL-12 thus has potential to promote an immune response, enhance the host defense response (517), and treat Th2-driven imbalances such as allergy or asthma. Evidence for its role in protective immunity is supported by the finding that individuals who lack the ability to express a component of the IL-12 receptor (IL-12RjSl) are susceptible to bacterial infection (518,519). 

A. Upregulation of Normal Receptor Expression as Part of a Host Defense Response... 

II. Upregulation of receptor expression as part of host defense response... 

Kluger, M. J. and Rothenburg, B, A. (1979) Fever and reduced iron their interaction as a host defense response to bacterial infection. Science 203 374-376. 

The preceding description of nodule initiation, development, and nitrogen-ase clearly demonstrates that the host contribution to symbiosis can be grouped into several functions, including recognition, root hair invasion, infection thread formation, nodule differentiation (e.g., meristems, vascular elements, sclerenchyma), carbon assimilation, organic acid production, ammonia assimilation, maintenance of low O2 by Lb, separation of bacteroids and host cytoplasm by the PBM, senescence, and possibly suppression of host defense responses required for nodule compatibility and/or effectiveness. 

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