The overall goal of this project is to further our understanding of the molecular basis of host-parasite interactions of Cryptosporidium parvum in order to develop specific preventive and therapeutic strategies for cryptosporidiosis. C. parvum is a significant cause of human gastrointestinal disease worldwide. In immunocompromised hosts, such as AIDS patients, C. parvum may cause severe, protracted and ultimately fatal disease. There is currently no effective specific therapy for the disease caused by this parasite. This proposal is focused on elucidating the molecular basis for the interaction of gp40 and gp 15 with host cells and on characterization of the post-translational processing and modifications of gp40/15 and its products, which may facilitate the identification of novel biochemical targets for future drug discovery. These glycoproteins are likely to be involved in attachment and invasion since they are present on the surface of invasive stages of the parasite, bind to host cells, competitively inhibit invasion, and are targets of infection-neutralizing antibodies and lectins. They are derived by proteolytic cleavage of a precursor protein gp40/15 which is encoded by a single copy gene, Cpgp40/15. This gene is highly polymorphic, particularly in human (genotype I) isolates. In the first Specific Aim, the role of these proteins in mediating attachment and invasion will be examined in detail. Binding of native C parvum gp40 and gpl5 as well as recombinant gp40 and gpl5 (derived from isolates of both genotype) to host cells will be assessed. The ability of the recombinant proteins to inhibit infection in vitro will be determined. The structural basis of attachment of gp40 and gpl5 to host cells will be determined by site-directed mutagenesis. Host cell receptors for gp40 and gpl5 will be identified. In the second Specific Aim, post-translational processing of the precursor protein gp40/15 will be investigated and studies on the protease involved in processing initiated. Glycosylation of these glycoproteins will be examined. The long-term objective is to determine if infection by this parasite can be prevented or treated by targeting molecules such as these glycoproteins as well as enzymes involved in their post-translational processing and modifications.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI052786-04
Application #
7061691
Study Section
AIDS and Related Research 8 (AARR)
Program Officer
Rogers, Martin J
Project Start
2003-04-15
Project End
2008-03-31
Budget Start
2006-04-01
Budget End
2007-03-31
Support Year
4
Fiscal Year
2006
Total Cost
$347,502
Indirect Cost
Name
Tufts University
Department
Type
DUNS #
079532263
City
Boston
State
MA
Country
United States
Zip Code
02111
Wanyiri, Jane W; Kanyi, Henry; Maina, Samuel et al. (2014) Cryptosporidiosis in HIV/AIDS patients in Kenya: clinical features, epidemiology, molecular characterization and antibody responses. Am J Trop Med Hyg 91:319-28
Bhat, Najma; Wojczyk, Boguslaw S; DeCicco, Maria et al. (2013) Identification of a family of four UDP-polypeptide N-acetylgalactosaminyl transferases in Cryptosporidium species. Mol Biochem Parasitol 191:24-7
Sarkar, Rajiv; Ajjampur, Sitara Swarna Rao; Muliyil, Jayaprakash et al. (2012) Serum IgG responses and seroconversion patterns to Cryptosporidium gp15 among children in a birth cohort in south India. Clin Vaccine Immunol 19:849-54
Borad, Anoli J; Allison, Geneve M; Wang, David et al. (2012) Systemic antibody responses to the immunodominant p23 antigen and p23 polymorphisms in children with cryptosporidiosis in Bangladesh. Am J Trop Med Hyg 86:214-22
Hira, Kirthi G; Mackay, Melanie R; Hempstead, Andrew D et al. (2011) Genetic diversity of Cryptosporidium spp. from Bangladeshi children. J Clin Microbiol 49:2307-10
Ajjampur, Sitara Swarna Rao; Sarkar, Rajiv; Allison, Geneve et al. (2011) Serum IgG response to Cryptosporidium immunodominant antigen gp15 and polymorphic antigen gp40 in children with cryptosporidiosis in South India. Clin Vaccine Immunol 18:633-9
Allison, Genève M; Rogers, Kathleen A; Borad, Anoli et al. (2011) Antibody responses to the immunodominant Cryptosporidium gp15 antigen and gp15 polymorphisms in a case-control study of cryptosporidiosis in children in Bangladesh. Am J Trop Med Hyg 85:97-104
Chatterjee, Anirban; Banerjee, Sulagna; Steffen, Martin et al. (2010) Evidence for mucin-like glycoproteins that tether sporozoites of Cryptosporidium parvum to the inner surface of the oocyst wall. Eukaryot Cell 9:84-96
Bhat, Najma; Joe, Angela; PereiraPerrin, Mercio et al. (2007) Cryptosporidium p30, a galactose/N-acetylgalactosamine-specific lectin, mediates infection in vitro. J Biol Chem 282:34877-87
Rogers, K A; Rogers, A B; Leav, B A et al. (2006) MyD88-dependent pathways mediate resistance to Cryptosporidium parvum infection in mice. Infect Immun 74:549-56

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