Herpesvirus papio 2: alternative antigen for use in monkey B virus diagnostic assays

BACKGROUND AND PURPOSE: Serologic testing for antibody to monkey B virus (BV) in macaque sera is problematic due to the biohazardous nature of BV and BV antigens. Herpesvirus papio 2 (HVP2), a herpesvirus of baboons, is more closely related genetically and antigenically to BV than is human herpes simplex virus 1 (HSV1). The potential for use of HVP2 relative to HSV1 as an alternative test antigen for detection of anti-BV antibody in macaque sera was assessed. METHODS: Standard ELISA formats were developed, using BV-, HVP2-, and HSV1-infected cell extracts. Performance of the HVP2 and HSV1 tests was assessed relative to that of the BV test. RESULTS: Using the BV antigen ELISA, 349 sera from 7 macaque species were tested, and results were classified as positive (253), negative (94), or suspect (2). The ELISA using HVP2 antigen detected 98.0% of BV-positive sera (248 of 253), whereas the HSV1-based ELISA detected only 96.0% (243 of 253). All three ELISAs identified the same two samples as suspect, and the HSV1 ELISA identified three additional BV-positive sera as suspect. CONCLUSIONS: The HVP2 antigen-based ELISA was equal in sensitivity and specificity to the BV antigen-based ELISA and was superior to the HSV1 ELISA for detection of BV-positive macaque sera. In addition, the HVP2 ELISA has greater laboratory safety, compared with BV antigen use for ELISA testing.     

Role of the cytomegalovirus (CMV)-antigenemia assay as a predictive and follow-up detection tool for CMV disease in AIDS patients

Forty-two patients were evaluated to determine the value of the CMV antigenemia (CMV-Ag) test as a follow-up marker as well as a prediction marker of CMV disease. Twenty patients were positive for at least one positive CMV-Ag assay and 9 of them developed CMV retinitis. With the threshold value (10 positive cells), sensitivity was 56% and specificity was 94%. The CMV-Ag assay, with the threshold value, produced high specificity, positive predictive value and negative predictive value but relatively poor sensitivity. Eight patients experienced CMV disease relapse a total of 16 times. At relapse, 8 of the 16 times showed negative for CMV-Ag assay; 7 underwent systemic maintenance while 1 underwent local maintenance. It is inferred that the CMV-Ag test is a poor follow-up marker to detect the relapse of CMV disease, particularly in patients undergoing systemic maintenance.     

Problems posed by the preparation of specific anti-cytomegalovirus immunoglobulins

The authors describe the preparation of a first batch of intravenous cytomegalovirus (CMV) immune globulin at the Nancy Regional blood transfusion centre. Immune plasmas were selected from 3 640 healthy volunteer blood donors on the basis of CF antibody titers to CMV (Kolmer's method modified) of, at least, 1:8; plasmas from approximately 10% of the donors were therefore selected. The 68 liters of pooled immune plasma had à CF antibody titer of 1:16 (CMV antibody titers of 1: 10 000 and 1: 640 when tested in the ELISA assay and passive hemagglutination assay respectively). Intravenous immune globulin was produced from pooled plasma by Cohn fractionation and treatment with pepsin at pH 4; 4.8 liters of immune globulin were prepared and divided in 96 doses of 50 ml each. The final product was found to have a CMV antibody titer of 1: 32 (CF) 1: 50 000 (ELISA) or 1: 2 560 (passive hemagglutination). Recent reports on the preparation of CMV immune globulin are briefly reviewed.     

Comparison of serological methods and blood culture for detection of Trypanosoma cruzi infection in raccoons (Procyon lotor)

The indirect immunofluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA) were compared with blood culture for the detection of Trypanosoma cruzi infection in 83 raccoons (Procyon lotor) trapped in 4 counties of southeast Georgia. Both IFAT and ELISA detected 24 of 25 culture-positive samples (96% sensitivity). Cultures from 25 raccoons (30%) were positive for epimastigotes, whereas a total of 50 raccoons (60%) was seropositive by either the IFAT or ELISA. Forty-five of 83 serum samples (54%) were positive for anti-T. cruzi antibodies with the ELISA, and 47 were IFAT positive (57%). Forty-two of the 50 seropositive raccoons (84%) were seropositive by both tests. Endpoint titers of IFAT-positive samples were determined by testing doubling dilutions from 1:40 to 1:1280. High titers of 640 and 320 were observed for 4 raccoons trapped in 1 county (St. Catherines Island, Liberty County) and titers of 160 for 1-2 raccoons from each of the 4 counties sampled. IFAT titers and ELISA optical density values were positively correlated. Both serological tests have a high sensitivity and should be excellent tools for studying the prevalence of T. cruzi in wildlife populations.     

Anti-CeHV1 antibodies of two cynomolgus macaques cross-react with HSV2 but not HSV1 antigens in ELISA

BACKGROUND: The aim of the study was to compare the cross-reactivity of macaque anti-CeHV1 antibodies with type 1 and type 2 human herpes simplex viruses (HSV1 and HSV2). METHODS: We studied the serum of 344 animals which had been tested either positive (n = 39) or negative (n = 305) for the presence of CeHV1 antibodies by expert laboratories. Macaque serums were studied by means of two ELISA: one based on HSV1 antigen-coated wells, the other on polystyrene beads coated with HSV1 and HSV2 antigens in approximately equal proportions. RESULTS: In the serum of two animals originating from Vietnam, we found anti-CeHV1 antibodies cross-reacting with HSV2 but not with HSV1 antigens. For the serum with the highest titer, inhibition by soluble antigens confirmed the high affinity of the antibodies for HSV2 antigens. CONCLUSIONS: Tests using HSV1 and HSV2 in a combined way are better suited to macaque screening than tests using only HSV1 antigens.     

Antibodies against Toxoplasma gondii in the Pacific bottlenose dolphin (Tursiops aduncus) from the Solomon Islands

Serum samples from 58 Pacific bottlenose dolphins (Tursiops aduncus) from the Solomon Islands were tested for the IgG antibody to Toxoplasma gondii by the latex agglutination test (LAT), enzyme-linked immunosorbent assay (ELISA), and immunoblotting. The ELISA cut-off value was taken as OD > or = 0.276, and the final dilution ratio, recognized as positive, was represented by the end titer. In 25 of 58 samples, no antibody activity was detected by LAT and ELISA. In 8 of 58 samples, anti-T. gondii IgG antibodies were detected by both LAT and ELISA, with titers of greater than 1 : 64 and 1 : 160, respectively. By immunoblotting, the 8 serum samples producing higher titers showed specific antibody IgG binding to several antigens on the T. gondii lane, but not on the Neospora caninum lane. No specific bands were noted on the lanes for either parasite in the 25 serum samples for which no antibody activity was detected. The specific binding of IgG antibodies to T. gondii antigens observed for serum samples producing higher titers suggests that Pacific bottlenose dolphins from the Solomon islands are exposed to T. gondii.     

A new microplate neutralization test for typing of herpes simplex virus.

A microplate serum neutralization test for estimation of complement-requiring neutralizing (CRN) antibody was established as the first step for simplification of typing of herpes simplex virus (HSV). When guinea pigs were immunized with type 2 HSV, the late sera could mostly differentiate the types of HSV better than hyperimmune rabbit sera, the CRN titer against the heterologous type 1 HSV being much lower than the homologous titer. Sera of guinea pigs immunized with type 1 HSV showed about the same level of cross reaction against type 2 HSV as did rabbit antisera. Guinea pig sera having minimal levels of cross reaction were selected, and their high dilution (1:160) and complement were added to serial 10-fold dilutions of virus in the microplate titration of virus infectivity. Selective reduction of virus titer by either antiserum could determine the type of HSV. No equivocal intermediate case was found among a number of stock strains including many fresh isolates. The typing result coincided with that determined by a modification of Yang et al's method based on virus titers obtained with Vero and primary chick embryo cells. The typing based on plaquing in chick embryo cells sometimes failed to identify type 1 HSV.     

不同DNA提取法对腺病毒和细小病毒PCR检测效果评估

分别利用硫氰酸胍(Guanidine thiocyanate,GuScN)抽提法、螯合树脂处理法和蛋白酶K-酚/氯仿抽提法从粪便样品中制备腺病毒DNA(dsDNA)或细小病毒DNA(ssDNA)然后进行PCR检测。结果显示硫氰酸胍抽提法、螯合树脂处理法能有效地去除粪便中影响PCR扩增的抑制物,提高PCR检测的敏感性,而传统蛋白酶K-酚/氯仿抽提法不能有效地去除PCR扩增的抑制物,影响PCR检测结果。在检测粪便中腺病毒时,硫氰酸胍、螯合树脂和蛋白酶-酚/氯仿抽提法分别允许检测5TCID_{50相似文献}   

Syngeneic monoclonal anti-idiotype antibodies that bear the internal image of a human cytomegalovirus neutralization epitope

Two glycoproteins have been identified on human CMV that induce neutralizing antibody; an 86,000-Da glycoprotein and a 130,000-, 92,000-, and 50,000-Da glycoprotein coimmunoprecipitating complex that appears to be the gB homologue of HSV. We have produced syngeneic monoclonal anti-Id antibodies (mAb2) of the IgM isotype to a CMV-neutralizing monoclonal antibody (mAb1) that is known to bind to the 86,000-Da glycoprotein on the virion envelope. These mAb2 bear the internal image of the original viral antigen as shown by their ability to 1) recognize an interspecies idiotype in CMV-positive human antisera, 2) block mAb1 binding to CMV antigen, and 3) block CMV neutralization by mAb1 in vitro. Immunization of mice with both of these affinity chromatography-purified mAb2 stimulated the production of anti-anti-Id monoclonal antibodies (which we termed mAb3), which bound to the mAb2 by ELISA and neutralized CMV infectivity.