Abstract: The present invention provides a method of selecting virus vaccine candidates by selecting virus variants that do not bind to brain membrane receptor preparations, comprising the steps of: (a) preparing a brain membrane receptor preparation; (b) mixing an amount of a virus of interest with an amount of said membrane receptor preparation containing excess membrane receptors to form a virus-membrane receptor preparation suspension; (c) centrifuging said suspension to form a supernatant; (d) determining residual virus infectivity in said supernatant; and (e) isolating individual membrane receptor preparation binding-resistant virus variants which are useful as virus vaccine candidates.

Abstract: The present invention provides a Mycobacterium-E. coli shuttle vector containing sequences coding for a tribrid fusion containing the M. leprae 18kDa antigen sequence, a phoA protein antigen sequence and a non-mycobacterial, non-E.coli heterologous protein antigen sequence. Also provided is a method of producing protective immunity in an animal or human host in need of such treatment, comprising the step of administering to said animal or human host an effective dose of recombinant mycobacteria carrying the vector of the present invention.