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Inactivation of Human Immunodeficiency Virus Type 1 Infectivity With Preservation of Conformational and Functional Integrity of Virion Surface Proteins. Rossio et al. . Journal of Virology, Oct 1998, p 7992-8001 Presented by Allistair Abraham. Immunity and Vaccination .
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Inactivation of Human Immunodeficiency Virus Type 1 Infectivity With Preservation of Conformational and Functional Integrity of Virion Surface Proteins. Rossio et al.. Journal of Virology, Oct 1998, p 7992-8001 Presented by Allistair Abraham
Immunity and Vaccination • Body’s specific immune response is through antigen-antibody interaction • Vaccination enhances the body’s ability to illicit immune response • Active immunity (making own antibodies) • Artificial: vaccination involving part of virus, attenuated virus; basically “shots” • Natural: get the actual disease prior to re-infection
General focus of Study To create a vaccine using whole particle HIV-1 which has lost its ability to infect
Previous Methods of Removing Infectivity • Infectivity removed from viruses previously by • Heat • Formaldehyde fixation (Formalin) • Concern –these methods change protein conformation on the virus • Scientists want to find a method that does not change the conformation of the proteins
Removal of Infectivity by Altering of Zinc Finger Motifs • Zinc finger motifs are among the most highly conserved elements in retroviral sequences • Zinc finger motif – loop stabilized by interactions of Zinc atom and cysteine and histidine residues • Found in Nucleocapsid proteins
Removal of Infectivity by Altering of Zinc Finger Motifs • Subtle mutations causing sequence alteration lead to loss of infectivity • 2,2-dithiodipyridine or aldrithiol-2 (AT-2) removes zinc from loop
General Method • Viruses used – Different stocks of HIV-1 and SIV • Cells lines used- AA2, H9 and PHA blasts • Viral infectivity was inactivated by Heat, Formalin, and AT-2 • Infectivity and protein conformation and structure of virus was then observed
Precipitation of proteins by antibody addition • Human leukocyte antigen-I (HLA-I) and HLA-II are cellular proteins • gp 120 viral protein (48d and b12 are different antibodies) • H9 – antiserum raised against microvesicle preparations
Analysis of viral entry, uncoating and reverse transcription AZT/ddl inhibits reverse transcription Strong stop – indicates initiation of reverse transcription gag – protein formed by reverse transcription
Analysis of viral entry, uncoating and reverse transcription • AT-2 treatment prevents reverse transcription
Preservation of MHC class II reaction HIV-1 produced by MHC class II expressing cells • Measurement by T cell proliferation • MACS = macrophages • SEA = staphylococcal enterotoxin A (superantigen)
Conclusion • AT-2 was seen to inactivate infectivity effectively in HIV-1 • AT-2 did not cause conformational changes in the proteins of the virus as did Heat and formaldehyde treatment
In the Future….. • AT-2 treatment should be useful for HIV-1 blood analysis • Vaccines formed should be more effective as suggested by previous research