Detection Of Type-specific Antibodies Research Articles

Linear Multiepitope (Glyco)peptides for Type-Specific Serology of Herpes Simplex Virus (HSV) Infections.

Detection of type-specific antibodies is an important and essential part of accurate diagnosis, even in silent carriers of herpes simplex virus (HSV)-1 (oral) and HSV-2 (genital) infections. Serologic assays that identify HSV-1 and HSV-2 type-specific antibodies have been commercially available for more than a decade but often face problems related to cross-reactivity and similar issues. Attempts to identify type-specific peptide epitopes for use in serology for both HSV-1 and HSV-2 have been limited. We recently demonstrated epitope mapping of envelope glycoprotein G2 and identified a type-specific glycopeptide epitope that broadly recognized HSV-2 infected individuals. In the present work we have performed a comprehensive glycopeptide synthesis and microarray epitope mapping of 14 envelope proteins from HSV-1 and HSV-2, namely, gB, gC, gD, gE, gG, gH, and gI, using sera from HSV-1- and HSV-2-infected individuals and control sera. Several unique type-specific peptide epitopes with high sensitivity were identified and synthesized as one large linear multiepitope sequence using microwave-assisted solid-phase (glyco)peptide synthesis. Microarray validation with clinically defined HSV and Varicella Zoster (VZV) sera confirmed excellent cumulative specificities and sensitivities.

Molecular Epidemiology of Hepatitis C Virus Infection in Dialysis Patients

There are very few data on the molecular biology of hepatitis C virus (HCV) infection in dialysis patients. 101 patients undergoing dialysis treatment in 4 units in the Lombardy, northern Italy, were analyzed by RT-PCR for HCV viremia, by line probe assay technology for HCV genotyping and by a serological analysis for detecting type-specific antibodies. 61 of 101 (60%) patients showed detectable HCV RNA in serum; HCV genotype 2a was dominant (30/53 = 57%), followed by HCV genotype 1b (20/53 = 37%). There was no relationship between HCV genotyping and the clinical or demographic features of the patients. The antibody response toward the c33-c, c100-3, and 5-1-1 antigens was more frequent in HCV genotype 1b compared with genotype 2a (p = 0.046, p = 0.001 and p = 0.0001, respectively). The antibody levels to NS-3 and NS-4 HCV proteins were significantly higher in patients with-HCV genotype 1b in comparison with HCV 2a-infected individuals (p = 0.0001). There was a high level (82%) of agreement between HCV genotyping by RT-PCR and the assessment of type-specific antibodies by serological analysis; further, it was possible to detect type-specific antibodies in 6 of 22 (27%) patients in whom PCR amplification was unsuccessful. In conclusion, HCV subtype 2a was dominant in our population of HCV-infected dialysis patients, dialysis patients infected by different genotypes showed similar demographic and clinical characteristics, the antibody response toward the NS-3- and NS-4-related antigen of HCV was genotype dependent. There was a high level of agreement between HCV genotyping by RT-PCR and the detection of type-specific antibodies by serological analysis. As significant biological differences may exist among HCV strains, the assessment of HCV types may be very useful in the routine clinical activity of nephrologists in dialysis units.

Prevalence of hepatitis C genotypes among patients with chronic hepatitis C in Norway. Construct Group.

Among 116 patients with biopsy-confirmed chronic hepatitis C (Riba 2 or Riba 3 positive) in a multicenter study in southern Norway on interferon, we determined hepatitis C virus genotype by restriction fragment length polymorphism (RFLP) of the 5' NCR. The RFLP method was supplemented by and compared with a serological typing method based on the detection of type-specific antibody to peptide from the NS-4 region. A total of 102/106 (96%) patient sera showed detectable type-specific antibody to NS-4 peptides and corresponded in all cases, except two, to the genotype detected by polymerase chain reaction. Combining the results from RFLP genotyping and serotyping, genotype 1 was found in 40 (35%) (27 with 1a and 10 with 1b, 3 subtypes not determined), genotype 2 in 15 (13%) (subtype 2b in 14 and 1 subtype not determined), and genotype 3 in 58 (50%) of patients. The low mean age of the patients (34 years), the low prevalence of cirrhosis (3.5%), the short duration of the disease, and a high prevalence of intravenous-drug abusers may account for the low prevalence of infection with genotype 1b (9%). The epidemiological features of hepatitis C patients are markedly different from patient groups described in southern Europe in terms of risk factors, age, and genotype distribution.

Studies on the Neutralizing Antibody to Herpes Simplex Virus: III. Detection of Type-Specific Antibody by Slow-Reacting Complement-Requiring Neutralizing Antibody Assay.

The type-specific antibody responses in rabbits immunized with both types of herpes simplex virus (HSV), measured by complement-requiring neutralizing (CRN) and slow-reacting CRN (s-CRN) antibody assays were compared. Titers of type-specific antibody measured by s-CRN antibody assay were always markedly higher than those measured by CRN antibody assay. The s-CRN antibody assay was so sensitive that even an undetectable level of CRN antibody could be readily detected by this method. The detection of type-specific antibody by s-CRN antibody assay may be useful when attempting to analyze human HSV infection.

Studies on the binding between streptococcal M protein and antibody.

A method for detecting type-specific antibody to type 12 beta-hemolytic streptococci is described. The method is based on the utilization of a partially purified I(131) labeled streptococcal acid extract and the solubility of this extract in 40 per cent saturated ammonium sulfate as compared to the insolubility of antibody and antigen-antibody complexes at this salt concentration. The salient features of this technique are: (a) When absorbed sera were used, no non-type-specific reaction with antigen occurred. (b) The sensitivity of the system allowed detection of type-specific antibody in hyperimmune antisera that had been diluted 1200-fold. (c) The method does not rely on secondary manifestations of antigen-antibody interaction for the detection of antibody. (d) As little as 0.03 microg of M(12) protein was detected when soluble unlabeled M protein was used to inhibit the reaction between I(131) M(12) protein and anti-M(12) antibody. (e) The kinetics of the reaction between M protein and anti-M antibody can be studied, thereby making information available as to the quality as well as the quantity of antibody produced in this antigen-antibody system.