Prevalence of intestinal pathogens in HIV patients with diarrhea: implications for treatment

Prediction of HIV-1 virus-host protein interactions using virus and host sequence motifs

Background

Host protein-protein interaction networks are altered by invading virus proteins, which create new interactions, and modify or destroy others. The resulting network topology favors excessive amounts of virus production in a stressed host cell network. Short linear peptide motifs common to both virus and host provide the basis for host network modification.

Methods

We focused our host-pathogen study on the binding and competing interactions of HIV-1 and human proteins. We showed that peptide motifs conserved across 70% of HIV-1 subtype B and C samples occurred in similar positions on HIV-1 proteins, and we documented protein domains that interact with these conserved motifs. We predicted which human proteins may be targeted by HIV-1 by taking pairs of human proteins that may interact via a motif conserved in HIV-1 and the corresponding interacting protein domain.

Results

Our predictions were enriched with host proteins known to interact with HIV-1 proteins ENV, NEF, and TAT (p-value < 4.26E-21). Cellular pathways statistically enriched for our predictions include the T cell receptor signaling, natural killer cell mediated cytotoxicity, cell cycle, and apoptosis pathways. Gene Ontology molecular function level 5 categories enriched with both predicted and confirmed HIV-1 targeted proteins included categories associated with phosphorylation events and adenyl ribonucleotide binding.

Conclusion

A list of host proteins highly enriched with those targeted by HIV-1 proteins can be obtained by searching for host protein motifs along virus protein sequences. The resulting set of host proteins predicted to be targeted by virus proteins will become more accurate with better annotations of motifs and domains. Nevertheless, our study validates the role of linear binding motifs shared by virus and host proteins as an important part of the crosstalk between virus and host.

Antibody responses to Cryptosporidium antigen in HIV-positive patients in the Republic of Korea

The diagnosis of cryptosporidiosis has been carried out using coprologic techniques in the Republic of Korea. However, antibody responses to Cryptosporidium have rarely been studied. Serum antibodies from HIV-positive/oocyst-positive Korean patients recognized significantly 31 and 27 kDa antigens, and HIV-negative/oocyst-positive individuals clearly reacted to 15/17 kDa antigens. Compared with oocyst-positive cases, 18.7% and 75.8% of sera from HIV-positive patients reacted to 31 and 27 kDa antigens. Only 11.1% of HIV-negative individuals reacted to 15/17 kDa. Based on these findings, serum antibody responses were different between HIV-positive and HIV-negative individuals infected with Cryptosporidium, and it is suggested that HIV-positive patients are more frequently exposed to C. parvum compared to HIV-negative individuals.

The Impact of Nutrition on Physiologic Changes in Persons Who Have HIV

HIV affects almost all bodily systems, which can lead to recurrent opportunistic infections, weight loss, distribution of weight changes, and death. Malnutrition and wasting, two symptoms that interfere with nutrient availability, accessibility, and metabolism, are associated with higher morbidity and mortality. Nausea, vomiting, swallowing or chewing difficulties, or the response of the body to opportunistic infections or medications that are considered vital to the treatment of the disease may affect nutritional status. A positive nutritional balance may help to improve the immune and other body systems, and delay the progression of the disease, This article reviews the effect of the nutritional status on the physiologic changes in the person who is infected with HIV.

Critical Role of T Cell-Dependent Serum Antibody, but Not the Gut-Associated Lymphoid Tissue, for Surviving Acute Mucosal Infection withCitrobacter rodentium, an Attaching and Effacing Pathogen

Citrobacter rodentium uses virulence factors similar to the enteropathogenic Escherichia coli to produce attaching and effacing lesions in the distal colon of mice. We used this infection model to determine components of adaptive immunity needed to survive infection. During acute infection, wild-type mice develop breaks across infected epithelial surfaces but resolve infection. Surprisingly, mice markedly deficient in mucosal lymphocyte populations from beta(7) integrin deficiency resolve infection, as do CD8alpha-/- or TCR-delta-/- mice. In contrast, CD4-/- or TCR-beta-/- mice develop polymicrobial sepsis and end-organ damage, and succumb during acute infection, despite epithelial damage similar to wild-type mice. B cell-deficient (MuMT-/-) or B and T cell-deficient (recombinase-activating gene 2-/-) mice develop severe pathology in colon and internal organs, and deteriorate rapidly during acute infection. Surviving mice develop robust Citrobacter-specific serum IgM responses during acute infection, whereas mice that succumb do not. However, CD4-/- mice receiving serum Igs from infected wild-type mice survive and clear the infection. Our data show that survival of apparently self-limited and luminal mucosal infections requires a systemic T cell-dependent Ab response against bacteria that enter through damaged mucosa. These findings have implications for understanding host defense against mucosal infections, including the pathogenesis of these diseases in immunocompromised populations.