Intracellular pathogens

Recently, another interaction was reported between an intracellular pathogen and the key regulator system of intracellular iron concentration, i.e. the degree of binding of the IRPs to IRE (see Chapter 7). In extracts from Leishmania tarentolae, a protein has been detected that binds specifically to the mammalian IRE. However, the exact nature and function of this protein is unclear up to now. In contrast to mammalian IRPs, the L. tarentolae IRE-binding activity was not induced by growth in iron-depleted medium (Meehan et ah, 2000). 

Genome loss and specific host adaptive features in obligate intracellular pathogens... 

Gruenheid, S., Pinner, E., Desjardins, M. and Gros P. (1997). Natural resistance to infection with intracellular pathogens the Nrampl protein is recruited to the membrane of the phagosome, J. Exp. Med., 185, 717-730. 

The immune system protects humans and animals from microbial infections by such infectious agents as bacteria, yeasts and fungi, viruses and protozoa. These differ greatly not only in their size but in their structural and molecular properties, as well as in the ways in which they seek to infect our bodies. Some of these pathogens infect bodily fluids, some penetrate tissues and some even survive and multiply within individual host cells. These intracellular pathogens include viruses, some parasitic protozoa (such as Plasmodium, the causative agent of malaria, which infects erythrocytes) and... 

Redpath S, Ghazal R Gascoigne NR Hijacking and exploitation of IL-10 by intracellular pathogens. Trends Microbiol 2001 9 86-92. 

Conlan JW, et al. Immunization of mice with lipopeptide antigens encapsulated in novel liposomes prepared from the polar lipids of various Archaeobacteria elicits rapid and prolonged specific protective immunity against infection with the facultative intracellular pathogen. Listeria monocytogenes. Vaccine 2001 19 3509. 

IRIV adjuvance in hepatitis A vaccination has been demonstrated as enhancement of humoral responses (1). There are only few adjuvants licensed for human use and they predominantly enhance humoral immune responses (2-4). In view of chronic viral diseases, infections linked to intracellular pathogens, and cancer immunotherapy, there is a need for appropriate adjuvants that have the capability to enhance cellular immune responses, in particular cytotoxic T-cell (CTL) responses (4,5). Here, we addressed IRIV-elicited immune responses and IRIV capacity to enhance CTL responses. 

Adjuvants enhancing HLA class I-restricted CTL responses are especially needed for treatment or prevention of chronic viral diseases and infections linked to intracellular pathogens, and for cancer immunotherapy. Among the very few adjuvants licensed for human use, we evaluated the capacity of IRIV to enhance HLA class I-restricted CTL responses in vitro. We addressed IRIV-elicited immune responses and the induction of CTL specific to IM58 66 and Melan-A/Mart-127-35 epitopes. Proliferation assays, cytokine expression studies, and phenotypes of CD4+ T-cells demonstrated that IRIV... 

Yersinia enterocolitica Proliferation in gut associated lymphoid tissue (facultative intracellular pathogen)(heat stable enterotoxin, LPS, invasin, attachment/invasion protein adhesion Ail) Bacillus cereus Emetic toxin (vomiting) Enterotoxins (diarrheal illness) ... 

Partitioning of some drugs into cells occurs. Red blood cells parasitized by malaria selectively take up chloroquine, which accounts in part for the efficacy of this antimalarial against intracellular malarial forms. The intrahepatocellular concentration of chloroquine is 500 times that of the blood plasma concentration. Macrolides and fluoroquinolones are also selectively partitioned into cells, which accounts in part for their efficacy against mycoplasma and chlamydia, both intracellular pathogens. 

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