Molecular Biology and Epidemiology for Control of Rotavirus Diarrhea 
Rotavirus infections are limited to the gut, and 
it is believed that a vaccine will have to be given 
orally to stimulate a local (mucosal) immune re- 
sponse in order to induce protection. An attrac- 
tive approach to this, alternative to the use of live 
attenuated virus, is the use of live oral vaccines 
containing nonpathogenic strains of enteric bac- 
teria carrying the genes that code for the protec- 
tive rotavirus antigens. We are currently con- 
structing expression vectors to direct the 
synthesis of the surface proteins of rotavirus in 
the enteric bacteria Salmonella and Lactobacil- 
lus, and will test the potential of these recombi- 
nant strains to induce a protective immune re- 
sponse against rotavirus infection. 
Finally, our laboratory is also interested in the 
study of some aspects of the epidemiology of ro- 
tavirus. Six different serotypes of human rotavir- 
uses have been identified, four of which appear 
to account for the majority of isolates. We have 
found that the four major serotypes circulate in 
Mexico. We are currently studying the molecular 
determinants of virulence of rotavirus and inves- 
tigating how the frequency of the different sero- 
types changes over time and in relation to 
virulence. 
In situ localization o/c-kit and Steel ex- 
pression in adult mouse cerebellum. The 
protein products of the proto- oncogene 
c-kit and its ligand, the protein product 
of the Steel gene, interact to activate Kit 
tyrosine kinase activity vital to the func- 
tion of melanocytes, blood cells, and 
germ cells. The abbreviations identify 
the molecular layer (mol), granular 
layer (gran), and Purkinje cells (Pur). 
From Motro, B., van der Kooy, D., 
Rossant, f., Reith, A., and Bernstein, A. 
1991. Development 115:1207-1221. 
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