Encapsulated bacteria

The cancer patient and the HIV-positive patient are the two clinically important groups were the natural defence systems are disturbed either by the disease or by the treatment (chemotherapy, radiotherapy). Infections in the HIV-positive patient are discussed in Chapter 33B. Less prevalent immunocompromised hosts are patients with hypo- or agamma-globulinaemia or patients after splenectomy. These last patient groups with mainly humoral dysfunction generally suffer from infections by encapsulated bacteria S. pneumoniae, H. influenzae and N. meningitidis). In this section we will discuss patients with cellular immune dysfunction, mainly granulocytopenia. 

An important distinction must be made between the humoral response to a pure, capsular polysaccharide, and to the same polysaccharide when it is an integral part of the bacterium. Thus, the immunity received on recovery from infection by encapsulated bacteria, in terms of the polysaccharide antigen, differs from that generated by purposeful immunization with purified capsular-polysaccharide vaccines. Fortunately, with the exception of infants, the polysaccharide vaccines still stimulate protective-antibody levels in humans, despite these differences. In infants, due to the immature nature of their immune systems, these polysaccharide vaccines are of only marginal benefit.7 Some insights into the nature of these different responses in humans can be found in studies on the cellular basis of the immune response to polysaccharides. However, for the purposes of this Chapter, it would be inappropriate to provide a lengthy description of this incompletely understood mechanism in-depth reviews of this burgeoning field of research can be referred to.144-147,162-166... 

Iyer, C., and Kailasapathy, K. (2005). Effect of co-encapsulation of probiotics with prebiotics on increasing the viability of encapsulated bacteria under in vitro acidic and bile salt conditions and in yogurt. J. FoodSci. 70, M18-M23. 

Purswani M, Eickert S, Arora H, Johann-Liang R, Noel GJ. The effect of three broad-spectrum antimicrobials on mononuclear cell responses to encapsulated bacteria evidence for down-regulation of cytokine mRN A transcription by trovafloxacin. J Antimicrob Chemother 2000 46(6) 921-9. 

It has long been known that the presence or absence of CPS correlates in many cases with disease and that bactericidal and opsonic antibodies directed against them protect the host from invasive disease caused by encapsulated bacteria [2]. Antibodies directed against the LPS play also a major role in protection against infection by avoiding bacterial colonization of specific mucosa or organ [3]. 

Genetic Deficiency. Inherited primary deficiency of C3 is associated with a greatly increased risk for infection, particularly with encapsulated bacteria, similar to the picture seen with the Bruton type of agammaglobulinemia. Deficiency of the inactivators of C3, including factors H and I of the alternative pathway, is associated with severe secondary deficiency of C3 and a similar clinical picture. 

S. pneumoniae systemic model for encapsulated bacteria measure T-independent antibody response (LIAR)... 

The therapeutic agent should be further tested in the murine cytomegalovirus (MCMV) latent virus reactivation model if results from the influenza host resistance assay indicate a decreased functional activity for either NK, CTL, or TDAR, or a decrease in CD4+ cells as observed by immunopheno-typing. The MCMV latent virus reactivation model is discussed in detail below. The test article should be tested in the Streptococcus pneumoniae systemic model for encapsulated bacteria if immunophenotyping or histopathology, done in conjunction with the influenza host resistance model, reveals a decrease in the number of marginal zone B (MZB) cells. MZB cells are critical in host defense against bloodborne encapsulated bacteria and this host resistance assay is discussed in detail below. 

Then freshly obtained encapsulated lactobacilli bacteria are added to achieve a final concentration of at least 1 million viable bacteria per suppository. (Inasmuch as the goal is to achieve a final concentration of at least 1 million viable bacteria per suppository, a four- to sixfold excess of bacteria are usually added because some loss of the viability occurs during the various mixing processes. This means that about 500 mg of the encapsulated bacteria are usually added.) It is important to mix these organisms not only thoroughly to ensure uniformity but also quickly because moisture adversely affects the viability of the organisms. 

Avery wanted to be certain that the active agent was the DNA and not a small amount of protein contamination. To verify the result, a quantity of DNase, an enzyme that would destroy the DNA without affecting the protein, was prepared and added to the sample. When a portion of bacteria was tested, it could no longer transform the unencapsulated bacteria into encapsulated bacteria. Avery and his co-workers had conclusively proven that DNA was the transforming principle responsible for the development of polysaccharide capsules in the tmencapsulated bacteria. 

Eun, Y.-J. et al (2010) Encapsulating bacteria in agarose microparticles using microfluidics for high-throughput cell analysis and isolation. AC5 Chem. Biol, 6 (3), 260-266. 

The important role of anti-polysaccharide antibodies in protection from diseases caused by encapsulated bacteria was demonstrated in the seventies for Haemophilus influenzae type b. Neisseria meningitides and Streptococcus pneumoniae. 

Encapsulated bacteria. Streptococcus pneumoniae, Haemophilus influenzae. Neisseria meninp tidis... 

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