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Biomedical subjects

G Van der Groen

Publications and source records attributed to G Van der Groen.

At least 19 recordsLinked to original sources
PubMed1996

V3 loop sequence analysis of seven HIV type 1 group O isolates phenotyped in peripheral blood mononuclear cells and MT-2 cells.

HIV-1-infected individuals from which syncytium-inducing (SI) viruses are isolated most often progress more rapidly to AIDS than individuals carrying only non-syncytium-inducing (NSI) viruses. The syncytium-inducing capacity of virus isolates is commonly determined in conjunction to replication in MT-2 cells. Comparison of HIV-1 env sequences and a site-directed mutagenesis study have indicated that the presence of a positively charged amino acid at position 11 or 25 in the V3 loop is minimally required for the SI capacity of HIV-1 subtype B viruses. Studies have also shown a similar correlation between positively charged signature amino acids in the V3 loop and syncytium formation in MT-2 cells for HIV-1 subtypes A, D, and E. In the present study virus phenotype was determined and compared to the V3 loop sequence of seven HIV-1 group O isolates. Three of the HIV-1 group O isolates showed the NSI/non-MT-2 tropic phenotype and two showed the SI/MT-2 tropic phenotype, whereas two isolates presented an uncommon NSI/MT-2 tropic phenotype. The V3 loop of the two SI/MT-2 tropic isolates had a high net positive charge and contained a positively charged amino acid at position 11 or 25. The V3 loop of the two NSI/MT-2 tropic isolates had a low net positive charge and contained a single positively charged amino acid at position 37.

Amino Acid Sequence↗
PubMed1995

Virologic and serologic characteristics of a natural chimpanzee lentivirus infection.

This study set out to characterize the unique features of natural lentivirus infection in chimpanzees over time. The virologic and serologic characteristics of this infection were followed longitudinally in a naturally infected chimpanzee together with a small cohort of experimentally HIV-1-infected chimpanzees. The subsequent isolates from the naturally infected chimpanzee were all non-syncytium forming (NSI) versus syncytium forming in the experimentally infected animals. In contrast to HIV-1-infected chimpanzees virus load was higher and plasma viremia occurred but in a cyclic pattern. Serologic follow-up suggested the development of neutralizing antibodies with subsequent escape of new isolates. Interestingly, the sequence of the principal neutralizing (V3 loop) domain (of HIV-1) remained constant over time. Antibodies to peptides from the V3 loop were type specific. The occurrence of persistent, fluctuating plasma viremia and NSI-type virus variants of this natural lentivirus infection are unique characteristics not previously reported in experimentally infected chimpanzees.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Comparison of human immunodeficiency virus biological phenotypes isolated from cerebrospinal fluid and peripheral blood.

Quantitative human immunodeficiency virus (HIV) cultures were carried out on cerebrospinal fluid (CSF), peripheral blood mononuclear cells (PBMCs), and plasma from patients with HIV in order to compare the infectious HIV load. The HIV strains isolated were studied for syncytium-inducing (SI) capacity, using the MT-2 cell line, in order to compare the HIV strain phenotype of blood and CSF isolates. Forty-two patients with HIV-1 infection were enrolled in the study, 33 of whom had neurological symptoms and 9 of whom were without neurological symptoms. HIV was isolated from 16 (38%) of the 42 CSF cultures, with a low mean titer of 6.3 +/- 3.4 tissue-culture-infective doses (TCID) per milliliter. Patients with HIV-positive CSF culture had a viral load in PBMCs of 40.5 +/- 15.5 TCID per 10(6) PBMC and in plasma of 104.7 +/- 9.3 per milliliter. Two (15%) of the 13 CSF isolates were SI strains, compared to 17 (56.6%) of the 30 PBMC isolates and 13 (54%) of the 24 plasma isolates (P < 0.05). Five of the nine patients from whom CSF and blood strains were obtained had the same viral biological phenotype. This study suggests that different HIV variants may be found in different body fluids and/or cells.

Adult↗
PubMed1994

Effect of methodology on detection of HIV-1/HIV-2 dual infections in Côte d'Ivoire.

Dual seroreactivity to the human immunodeficiency virus (HIV) types 1 and 2 is common in Côte d'Ivoire. To assess whether dual infection is the reason for dual seroreactivity, different methods for detection of HIV-1 and HIV-2 viruses were compared. PCR on primary uncultured lymphocytes of 56 dually seropositive samples revealed the presence of both HIV-1 and HIV-2 proviral DNA in 23 (41%) cases. In 7 other dual seropositive persons, PCR was carried out on the primary lymphocytes as well as on lymphocytes after 3 and 6 weeks of cocultivation. More cultures, 5/7 (71%), were positive for both viruses at 3 weeks compared to 0/7 at 6 weeks post cultivation. Moreover, 2 out of 3 samples, where only HIV-1 was detected in uncultured cells, were positive for both viruses after 3 weeks of cultivation. These data indicate that the sensitivity of HIV-2 detection can be increased by stimulation of patients' lymphocytes. A higher number of dual seropositive individuals (10/23 (48%)) had antibodies able to neutralize simultaneously both HIV-1 and HIV-2 prototype viruses than did HIV-1 antibody-positive sera (5/21 (24%)) or HIV-2 antibody positive sera (3/18 (17%)). The prevalence of dual seropositives being infected with both viruses is highly dependent on the method used to detect infection. There is a need to standardize virological markers in order to gain a better insight into the relative proportions of HIV-1, HIV-2 and HIV-1/HIV-2 dually infected persons.

Antibody Specificity↗
PubMed1991

Identification of Hantavirus serotypes by testing of post-infection sera in immunofluorescence and enzyme-linked immunosorbent assays.

Serum samples were collected from 27 individuals who had been infected with a member of the genus Hantavirus in the Netherlands or Belgium during the last 15 years. These samples were tested in an immunofluorescence assay (IFA) and two enzyme-linked immunosorbent assay (ELISA) systems, using different virus strains that represented each of the four recently proposed serotypes of this genus. The serum samples from 11 individuals who had been infected through contacts with laboratory rats showed the highest reactivities with Hantaan virus (serotype I) and SR-11 (serotype II) in the IFA and ELISA systems. The samples of 16 individuals who had probably been infected through contacts with wild rodents showed the highest reactivities with Hällnäs virus (serotype III) in the IFA. All except two of these also showed the highest reactivity with Hällnäs virus in the two different ELISA systems.

Antibodies, Viral↗
PubMed1988

Use of heat inactivated viral haemorrhagic fever antigens in serological assays.

Heating for 1 h at 60 degrees C completely destroyed the infectivity of sucrose-acetone-extracted antigen of Rift Valley (RVF) and Congo Crimean haemorrhagic fever (CCHF), as well as of RVF- and CCHF-infected mouse brain. These antigens could be successfully used, however, for complement fixation and IgM-capturing enzyme immunoassay. Vero E6 cell suspensions infected with hantaviruses such as Hantaan 76-118, Tchoupitoulas, SR 11, GB-B, CG 18-20, Hällnäs, CG 13891, Seoul and Prospect Hill, as well as Vero cells infected with CCHF and RVF viruses, were completely inactivated after heating for 1 h at 60 degrees C. Indirect immunofluorescent antibody test results obtained on slides prepared with heat-inactivated cell suspensions correlated well with results obtained on slides prepared with unheated cell suspensions. Inactivation is a simple, rapid, economic and reproducible method for inactivation of hantaviruses and CCHF and RVF viruses, with preservation of the ability to react specifically with antibodies.

Animals↗
PubMed1988

Acute HIV illness following blood transfusion in three African children.

Three children are described in whom pre-transfusion samples were HIV-seronegative and post-transfusional samples, obtained within 1 week after transfusion, were HIV-seropositive. Two of them developed a transient fever within 1 week of receiving the blood transfusion, and a transient generalized skin eruption which lasted for about 2 weeks. All three developed persistent generalized lymphadenopathy. One child developed a lumbar herpes zoster 7 months after transfusion. IgM Western blots demonstrated the presence of antibodies to protein bands p17, p24 and p55 in all three children. These three case reports suggest that children who receive a seropositive blood transfusion are at high risk for developing acute manifestations of HIV infection.

Acute Disease↗