Role of CSL glycoprotein in infectivity and neutralization of Cryptosporidium parvum sporozoites

Persistent Link:
http://hdl.handle.net/10150/282744
Title:
Role of CSL glycoprotein in infectivity and neutralization of Cryptosporidium parvum sporozoites
Author:
Langer, Rebecca Christine, 1972-
Issue Date:
1998
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Cryptosporidiosis, caused by the apicomplexan parasite Cryptosporidium parvum, has become a well recognized diarrheal disease of immunodeficient humans and other mammals throughout the world. Specific therapy and immunoprophylaxis are currently unavailable, but passive immunization with C. parvum-specific monoclonal antibodies (mAbs) has demonstrated efficacy in immunocompromised hosts. In particular, mAbs eliciting the circumsporozoite precipitate (CSP)-like reaction protected against C. parvum infection. The circumsporozoite-like antigen (CSL), an ∼1,300 kDa apical glycoprotein of sporozoites and merozoites, is the molecular species mechanistically bound by mAbs having the ability to elicit the CSP-like reaction. These findings indicated that CSL has a functional role in sporozoite infectivity. In the present study, a quantitative in vitro sporozoite infectivity assay was developed to evaluate neutralizing activity of mAbs. 3E2, a mAb which elicited the CSP-like reaction, demonstrated the greatest level of neutralizing activity against C. parvum infections. Here, I report that CSL has properties consistent with being a sporozoite ligand for epithelial cells. For these studies, CSL was isolated from sporozoites by isoelectric focusing (IEF). The 1,200-1,400 kDa Mᵣ region containing CSL in SDS-PAGE of sporozoites was comprised of 31 species when analyzed by two-dimensional electrophoresis. Eight species were present in IEF-isolated CSL. CSL specifically bound to Caco-2 cells in a dose-dependent, saturable, and self-displaceable manner with high affinity. CSL bound to Caco-2 cells inhibited the attachment and invasion of sporozoites in a dose-dependent manner. Characterization of the epitope recognized by 3E2 in a dot immunoblot indicated a β-glucose component. Sporozoites having undergone the CSP-like reaction after incubation with CSL-reactive 3E2, did not attach to or invade Caco-2 cells. These findings indicated that at least 1 of 8 CSL species isolated by IEF was a sporozoite ligand. The Caco-2 cell receptor for CSL was comprised of 16, 51, and 85 kDa molecules. Further, sporozoites incubated with isolated Caco-2 receptors failed to attach to and invade Caco-2 cells. Finally, CSL bound distinctly to receptors present on calf ileum. Based on these findings, I concluded that CSL ligand function is amenable to targeted disruption by CSL-reactive mAbs and that it is a rational target for immunization against cryptosporidiosis.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Biology, Veterinary Science.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Veterinary Science and Microbiology
Degree Grantor:
University of Arizona
Advisor:
Riggs, Michael W.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleRole of CSL glycoprotein in infectivity and neutralization of Cryptosporidium parvum sporozoitesen_US
dc.creatorLanger, Rebecca Christine, 1972-en_US
dc.contributor.authorLanger, Rebecca Christine, 1972-en_US
dc.date.issued1998en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractCryptosporidiosis, caused by the apicomplexan parasite Cryptosporidium parvum, has become a well recognized diarrheal disease of immunodeficient humans and other mammals throughout the world. Specific therapy and immunoprophylaxis are currently unavailable, but passive immunization with C. parvum-specific monoclonal antibodies (mAbs) has demonstrated efficacy in immunocompromised hosts. In particular, mAbs eliciting the circumsporozoite precipitate (CSP)-like reaction protected against C. parvum infection. The circumsporozoite-like antigen (CSL), an ∼1,300 kDa apical glycoprotein of sporozoites and merozoites, is the molecular species mechanistically bound by mAbs having the ability to elicit the CSP-like reaction. These findings indicated that CSL has a functional role in sporozoite infectivity. In the present study, a quantitative in vitro sporozoite infectivity assay was developed to evaluate neutralizing activity of mAbs. 3E2, a mAb which elicited the CSP-like reaction, demonstrated the greatest level of neutralizing activity against C. parvum infections. Here, I report that CSL has properties consistent with being a sporozoite ligand for epithelial cells. For these studies, CSL was isolated from sporozoites by isoelectric focusing (IEF). The 1,200-1,400 kDa Mᵣ region containing CSL in SDS-PAGE of sporozoites was comprised of 31 species when analyzed by two-dimensional electrophoresis. Eight species were present in IEF-isolated CSL. CSL specifically bound to Caco-2 cells in a dose-dependent, saturable, and self-displaceable manner with high affinity. CSL bound to Caco-2 cells inhibited the attachment and invasion of sporozoites in a dose-dependent manner. Characterization of the epitope recognized by 3E2 in a dot immunoblot indicated a β-glucose component. Sporozoites having undergone the CSP-like reaction after incubation with CSL-reactive 3E2, did not attach to or invade Caco-2 cells. These findings indicated that at least 1 of 8 CSL species isolated by IEF was a sporozoite ligand. The Caco-2 cell receptor for CSL was comprised of 16, 51, and 85 kDa molecules. Further, sporozoites incubated with isolated Caco-2 receptors failed to attach to and invade Caco-2 cells. Finally, CSL bound distinctly to receptors present on calf ileum. Based on these findings, I concluded that CSL ligand function is amenable to targeted disruption by CSL-reactive mAbs and that it is a rational target for immunization against cryptosporidiosis.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectBiology, Veterinary Science.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineVeterinary Science and Microbiologyen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorRiggs, Michael W.en_US
dc.identifier.proquest9906512en_US
dc.identifier.bibrecord.b3886244xen_US
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