Simple in vitro methods for titrating Feline Immunodeficiency Virus (FIV) and FIV neutralizing antibodies

1992 ◽  
Vol 37 (3) ◽  
pp. 241-252 ◽  
Author(s):  
Franco Tozzini ◽  
Donatella Matteucci ◽  
Patrizia Bandecchi ◽  
Fulvia Baldinotti ◽  
Alessandro Poli ◽  
...  
Keyword(s):  
Feline Immunodeficiency Virus ◽  
Neutralizing Antibodies ◽  
In Vitro Methods ◽  
Immunodeficiency Virus

scholarly journals Role of Env in Resistance of Feline Immunodeficiency Virus (FIV)-Infected Cats to Superinfection by a Second FIV Strain as Determined by Using a Chimeric Virus

2007 ◽  
Vol 81 (19) ◽  
pp. 10474-10485 ◽  
Author(s):  
Simone Giannecchini ◽  
Mauro Pistello ◽  
Patrizia Isola ◽  
Donatella Matteucci ◽  
Paola Mazzetti ◽  
...  
Keyword(s):  
Feline Immunodeficiency Virus ◽  
Neutralizing Antibodies ◽  
Viral Envelope ◽  
Lymphoid Cells ◽  
Time Interval ◽  
Complete Protection ◽  
Challenge Virus ◽  
Immunodeficiency Virus

ABSTRACT A more or less pronounced resistance to superinfection by a second strain of the infecting virus has been observed in many lentivirus-infected hosts. We used a chimeric feline immunodeficiency virus (FIV), designated FIVχ, containing a large part of the env gene of a clade B virus (strain M2) and all the rest of the genome of a clade A virus (a p34TF10 molecular clone of the Petaluma strain modified to grow in lymphoid cells), to gain insights into such resistance. FIVχ was infectious and moderately pathogenic for cats and in vitro exhibited the neutralization specificity of the env donor. The experiments performed were bidirectional, in that cats preinfected with either parental virus were challenged with FIVχ and vice versa. The preinfected animals were partially or completely protected relative to what was observed in naïve control animals, most likely due, at least in part, to the circumstance that in all the preinfecting/challenge virus combinations examined, the first and the second virus shared significant viral components. Based on the proportions of complete protection observed, the role of a strongly matched viral envelope appeared to be modest and possibly dependent on the time interval between the first and the second infection. Furthermore, complete protection and the presence of measurable neutralizing antibodies capable of blocking the second virus in vitro were not associated.

scholarly journals AIDS Vaccination Studies Using an Ex Vivo Feline Immunodeficiency Virus Model: Reevaluation of Neutralizing Antibody Levels Elicited by a Protective and a Nonprotective Vaccine after Removal of Antisubstrate Cell Antibodies

2001 ◽  
Vol 75 (9) ◽  
pp. 4424-4429 ◽  
Author(s):  
Simone Giannecchini ◽  
Daniela Del Mauro ◽  
Donatella Matteucci ◽  
Mauro Bendinelli
Keyword(s):  
Infected Cell ◽  
Feline Immunodeficiency Virus ◽  
Neutralizing Antibodies ◽  
Ex Vivo ◽  
Neutralizing Antibody ◽  
Cell Vaccine ◽  
Immunodeficiency Virus ◽  
Fixed Cell ◽  
Antibody Levels

ABSTRACT In the feline immunodeficiency virus system, immunization with a fixed-infected-cell vaccine conferred protection against virulent homologous challenge but the immune effectors involved remained elusive. In particular, few or no neutralizing antibodies were detected in sera from vaccinated cats. Here we show that, when preadsorbed with selected feline cells, the same sera revealed clearly evident virus-neutralizing activity. Because high titers of neutralizing antibody in cell-adsorbed sera from 23 cats immunized with fixed-infected-cell or whole-inactivated-virus vaccines correlated with protection, it is likely that they were more important for protection than formerly realized. In vitro, the fixed-cell vaccine efficiently removed neutralizing antibody from immune sera while the whole-inactivated-virus vaccine was much less effective.

scholarly journals Feline immunodeficiency virus (FIV) vaccine efficacy and FIV neutralizing antibodies

Vaccine ◽  
2014 ◽  
Vol 32 (6) ◽  
pp. 746-754 ◽  
Author(s):  
James K. Coleman ◽  
Ruiyu Pu ◽  
Marcus M. Martin ◽  
Ezra N. Noon-Song ◽  
Raphael Zwijnenberg ◽  
...  
Keyword(s):  
Feline Immunodeficiency Virus ◽  
Vaccine Efficacy ◽  
Neutralizing Antibodies ◽  
Immunodeficiency Virus

scholarly journals Feline Immunodeficiency Virus-Infected Cat Sera Associated with the Development of Broad Neutralization Resistance In Vivo Drive Similar Reversions In Vitro

2001 ◽  
Vol 75 (18) ◽  
pp. 8868-8873 ◽  
Author(s):  
Simone Giannecchini ◽  
Donatella Matteucci ◽  
Aldo Ferrari ◽  
Mauro Pistello ◽  
Mauro Bendinelli
Keyword(s):  
Tissue Culture ◽  
Feline Immunodeficiency Virus ◽  
Surface Glycoprotein ◽  
Virus Variant ◽  
Humoral Immune ◽  
Immunodeficiency Virus ◽  
Escape Mutants ◽  
Intervening Factors

ABSTRACT We previously reported that, upon reinoculation into cats, a neutralization-sensitive, tissue culture-adapted strain of feline immunodeficiency virus constantly reverted to the broad neutralization resistance typical of primary virus isolates and identified residue 481 in the V4 region of the surface glycoprotein as a key determinant of the reversion. Here, we found that well-characterized immune sera, obtained from cats in which such reversion had occurred, selected in tissue culture in favor of virus variants that also had a neutralization-resistant phenotype and had amino acid 481 changed, thus indicating that the host's humoral immune response is capable of driving the reversion in the absence of other intervening factors. In contrast, a second group of immune sera, elicited by a virus variant that had already reverted to neutralization resistance in independent cats, induced the emergence of escape mutants lacking broad neutralization resistance and neutralized fewer virus variants. It is proposed that the viral variants used to produce the two sets of sera may have generated different antibody repertoires.

scholarly journals In Vitro Activation of Feline Immunodeficiency Virus in Ramified Microglial Cells from Asymptomatically Infected Cats

2001 ◽  
Vol 75 (17) ◽  
pp. 8090-8095 ◽  
Author(s):  
Andreas Hein ◽  
Jean-Pierre Martin ◽  
Rüdiger Dörries
Keyword(s):  
Central Nervous System ◽  
Tissue Culture ◽  
Nervous System ◽  
Feline Immunodeficiency Virus ◽  
Mononuclear Cells ◽  
Central Nervous System Infection ◽  
Microglial Cells ◽  
Cell Contact ◽  
Immunodeficiency Virus

ABSTRACT Intravenous infection of cats with feline immunodeficiency virus was used as a model system to study activation of virus replication in brain-resident microglial cells in vitro. Virus release by ramified microglial cells isolated from subclinically infected animals was detectable in cell-free tissue culture supernatant only by reverse transcription and nested PCR of gag-specific RNA sequences and not by virion-associated reverse transcriptase activity. In contrast, cocultivation of in vivo-infected microglial cells with mitogen-activated peripheral blood mononuclear cells (PBMC) regularly allows detection of high virus yields in cell-free tissue culture fluid. Besides uptake and multiplication of microglia-derived virus in PBMC, release of virus from microglia is stimulated by cell contact with PBMC. The data suggest that T lymphocytes patrolling the central nervous system could reactivate the semilatent state of lentiviruses in microglial cells in the course of clinically silent central nervous system infection.

scholarly journals Altered Gag Polyprotein Cleavage Specificity of Feline Immunodeficiency Virus/Human Immunodeficiency Virus Mutant Proteases as Demonstrated in a Cell-Based Expression System

2006 ◽  
Vol 80 (16) ◽  
pp. 7832-7843 ◽  
Author(s):  
Ying-Chuan Lin ◽  
Ashraf Brik ◽  
Aymeric de Parseval ◽  
Karen Tam ◽  
Bruce E. Torbett ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Feline Immunodeficiency Virus ◽  
Ex Vivo ◽  
Expression System ◽  
Immunodeficiency Virus ◽  
A Cell ◽  
Virus Mutant ◽  
Substrate Inhibitor ◽  
Hiv 1

ABSTRACT We have used feline immunodeficiency virus (FIV) protease (PR) as a mutational system to study the molecular basis of substrate-inhibitor specificity for lentivirus PRs, with a focus on human immunodeficiency virus type 1 (HIV-1) PR. Our previous mutagenesis studies demonstrated that discrete substitutions in the active site of FIV PR with structurally equivalent residues of HIV-1 PR dramatically altered the specificity of the mutant PRs in in vitro analyses. Here, we have expanded these studies to analyze the specificity changes in each mutant FIV PR expressed in the context of the natural Gag-Pol polyprotein ex vivo. Expression mutants were prepared in which 4 to 12 HIV-1-equivalent substitutions were made in FIV PR, and cleavage of each Gag-Pol polyprotein was then assessed in pseudovirions from transduced cells. The findings demonstrated that, as with in vitro analyses, inhibitor specificities of the mutants showed increased HIV-1 PR character when analyzed against the natural substrate. In addition, all of the mutant PRs still processed the FIV polyprotein but the apparent order of processing was altered relative to that observed with wild-type FIV PR. Given the importance of the order in which Gag-Pol is processed, these findings likely explain the failure to produce infectious FIVs bearing these mutations.

scholarly journals The Infectious Molecular Clone and Pseudotyped Virus Models of Human Immunodeficiency Virus Type 1 Exhibit Significant Differences in Virion Composition with Only Moderate Differences in Infectivity and Inhibition Sensitivity

2009 ◽  
Vol 83 (17) ◽  
pp. 9002-9007 ◽  
Author(s):  
Nicholas M. Provine ◽  
Wendy Blay Puryear ◽  
Xueling Wu ◽  
Julie Overbaugh ◽  
Nancy L. Haigwood
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Pseudotyped Virus ◽  
Entry Inhibitors ◽  
Immunodeficiency Virus ◽  
Infectious Molecular Clones

ABSTRACT Two frequently employed methods for generating well-characterized, genetically defined infectious human immunodeficiency virus type 1 in vitro include the use of infectious molecular clones (IMCs) and pseudoviruses (PVs) competent for single-round infection. We compared six matched pairs of IMCs and PVs. The relative amounts of Env incorporated and efficiency of cleavage differed substantially between the two systems. Altering the ratio of proviral genome and env expression plasmids can produce pseudovirions that are structurally more similar to the matched IMCs. Differences in Env incorporation and cleavage translated into moderate differences in assays infectivity and sensitivity to neutralizing antibodies and entry inhibitors.

scholarly journals Breakthrough of SIV strain smE660 challenge in SIV strain mac239-vaccinated rhesus macaques despite potent autologous neutralizing antibody responses

2015 ◽  
Vol 112 (34) ◽  
pp. 10780-10785 ◽  
Author(s):  
Samantha L. Burton ◽  
Katie M. Kilgore ◽  
S. Abigail Smith ◽  
Sharmila Reddy ◽  
Eric Hunter ◽  
...  
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Neutralizing Antibodies ◽  
Rhesus Macaques ◽  
Neutralizing Antibody ◽  
Active Immunization ◽  
Antibody Responses ◽  
Challenge Virus ◽  
Gm Csf ◽  
Immunodeficiency Virus

Although the correlates of immunological protection from human immunodeficiency virus or simian immunodeficiency virus infection remain incompletely understood, it is generally believed that medium to high titers of serum neutralizing antibodies (nAbs) against the challenge virus will prevent infection. This paradigm is based on a series of studies in which passive transfer of HIV-specific nAbs protected rhesus macaques (RMs) from subsequent mucosal challenge with a chimeric human/simian immunodeficiency virus. However, it is unknown whether nAb titers define protection in the setting of active immunization. Here we determined serum nAb titers against breakthrough transmitted/founder (T/F) SIVsmE660-derived envelope glycoprotein (Env) variants from 14 RMs immunized with SIVmac239-based DNA-prime/modified vaccinia virus Ankara-boost vaccine regimens that included GM-CSF or CD40L adjuvants and conferred significant but incomplete protection against repeated low-dose intrarectal challenge. A single Env variant established infection in all RMs except one, with no identifiable genetic signature associated with vaccination breakthrough compared with T/F Envs from four unvaccinated monkeys. Breakthrough T/F Env pseudoviruses were potently neutralized in vitro by heterologous pooled serum from chronically SIVsmE660-infected monkeys at IC50 titers exceeding 1:1,000,000. Remarkably, the T/F Env pseudoviruses from 13 of 14 monkeys were also susceptible to neutralization by autologous prechallenge serum at in vitro IC50 titers ranging from 1:742–1:10,832. These titers were similar to those observed in vaccinated RMs that remained uninfected. These data suggest that the relationship between serum nAb titers and protection from mucosal SIV challenge in the setting of active immunization is more complex than previously recognized, warranting further studies into the balance between immune activation, target cell availability, and protective antibody responses.

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