MHV spike structure and neuropathogenesis : contributions of the receptor-binding domain and the heptad repeat region / Jean Ching-Yi Tsai.

Format:

Book

Manuscript

Microformat

Thesis/Dissertation

Author/Creator:

Tsai, Jean Ching-Yi.

Contributor:

Weiss, Susan R. (Susan Reich), advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Penn dissertations--Neuroscience.

Neuroscience--Penn dissertations.

Neurosciences.

Academic Dissertations as Topic.

Medical Subjects:

Neurosciences.

Academic Dissertations as Topic.

Local Subjects:

Penn dissertations--Neuroscience.

Neuroscience--Penn dissertations.

Physical Description:

xii, 243 pages : illustrations ; 29 cm

Production:

2002.

Summary:

The study of host-virus interactions provides insight into both viral and host strategies in pathogenesis. We have used the technique of targeted RNA recombination to investigate the importance of different regions of S, the MHV surface glycoprotein, in the early stages of viral infection as well as in virus spread.

Using recombinant viruses expressing wild-type or chimeric S, we demonstrated that the putative receptor-binding domain (RBD) in S conferred the ability to use soluble and cell surface CEACAMs. Viruses with MHV-A59 RBD associated with liposomes more efficiently and replicated to higher titers using CEACAM1 b than viruses with MHV-4 RBD in the chimeric S background. Our data suggested that CEACAM-independent fusion and spike lability affected the receptor use of the MHV-4 S-expressing virus in vitro and during infection.

In vivo, the viruses expressing chimeric spikes were attenuated in virulence and replication. Virus lability was characterized by the loss of infectious titers at high pH and temperature and has been associated with S1-S2 disassociation. Results showed that the most attenuated viruses were also the most resistant to neutralization. We hypothesized that the inverse relationship between thermostability and neurovirulence resulted from the decreased ability of the chimeric spikes to undergo structural rearrangement.

We further studied virus entry by generating recombinant viruses with point mutations in a heptad repeat region (HR1) of S, a region believed to be vital for spike structure as well as fusion function. Unlike the wild-type recombinant viruses, these recombinant mutant viruses depended on acid pH for virus entry. They were attenuated in vivo and restricted to the mouse olfactory bulb in antigen spread after intranasal inoculation. Thus, a single mutation in HR1 was sufficient to change the pH requirement of MHV entry and to inhibit virus spread in the CNS.

Our data suggested that both large sequence substitutions and point mutations in multiple regions of S may cause dramatic changes in S structure, possibly leading to a decrease in the thermolability. The study of the mechanism of attenuation of these recombinant viruses has contributed to our understanding of the relationship between MHV entry and pathogenesis.

Notes:

Supervisor: Susan R. Weiss.

Thesis (Ph.D. in Neuroscience) -- University of Pennsylvania, 2002.

Includes bibliographical references.

Local Notes:

University Microfilms order no.: 3043969.

OCLC:

244972725