Study Of Re-infection Children After Vaccination Frfr Mumps

Mumps virus (Muv) is a common human pathogen. Classical mumps infection presents as parotitis and complications such as pancreatitis ,orchitis and meningitis are frequent.tf Routine childhood vaccination with measles梞umps梤ubella (MMR)vaccine was introduced in the United Kingdom in 1988.The introduction of live attenuated mumps vaccine has successfully reduced laboratory梒onfirmed cases due to Muv by >90%.But small outbreaks continue to be identified.Muv is the member of paramyxovirus family. It is nonsegmented and has a single stranded negative sense RNA macromolecule of 15.3Kb.The genome contains 7structural proteins: The nucleocapsid regin(N),the phosphoprotein (P),the matrix (M),the large (L),the fusion(F),the haemagglutinin梟euraminidase protein (HN) and the small hydrophobic(SH) proteins. The SH coding region appears to be far morevariable than any other segments.Part one:Evaluation of immune status of refection childrenvaccinated for mumpsIn order to quest for the mumps梥pecific antibody levels of clinical specimens and normal controls after vaccination, acute serum samples were collected 6 days after onset of symptoms from 100 cases , corresponding specimens were collected from 50 children who had received measles梞umps梤ubella(MMR) vaccine at the same time but had remained well. The methods of indirect enzyme-linked immunosorbent assay (ELISA) was used to determine mumps virus antibody serum samples from 100 children vaccinated with a live attenuated mumps vaccine at the age (in years) of 1.5. The ELISA plates were coated with goat anti-human IGM and IGG antibodies. Mumps梥pecific IgG and IgM were detected in serum by ELISA(HOPE LABORATORIES MICROWELL ELISA KIT)with results expressed in terms of optical density (OD) values; IgG index =^1. 0 being positive.It showed that the positive ratio of IgG antibody is 96.7% The positive ratio of IGM is 84.8% in patients with parotitis, Eighteen serum samples showed serological evidence of re-infection with the absence of IgM and the presence of IgG antibodies in the acute serum. Three samples contained high IgM antibody titres and low or absent IgG litres characteristic of primary infection., the rest were IgG .IgM both positive. The positive percenty of IgG antibody in normal control is 92%, .The positive ratio of6IgM antibody in normal control is 4%.It was concluded that the patients exhibited a serological response characteristic of re梚nfection. In these cases, the vaccine had not protected against mumps. It is not known whether this was due to vaccine failure or waning immunity with time after vaccination. The antibody status of controls was consistent with prior immunity :mumps IgM was not detected and IgG was presentPart two:study on differentiation of Vaccine and Wild MumpsVirus by Polymerase chain reaction and nucleotidesequencing of the SH geneSerum samples were collected in the Ningbo area ZheJiang province during 2000?001 winter. All of the specimens were obtained from patients with a history of mumps vaccination. 100 refection children male 70,female 30,mean age 6.5 years old were studied. PCR tests for the SH gene were performed on the 100 cases. Mumps RNA was extracted from lOOul of specimen using the silica梘uanidinum thiocyanate method and reverse transcribed into cDNA with random primers. The laboratory strain used as PCR梡ositive control nested reverse transcription (RT) polymerase chain reaction (PCR) for the SH gene, to characterize MuV strains. The purified DNA fragment was sequenced using primers SH primerS with sequencing kit. The nucleotide (nt) sequence of the SH gene (318nt) was analysed. The. sequences were compared to those of wild type and vaccine strains of mumps.It revealed that. The SH gene is highly variable and has been used to7distinguish vaccine and wild梩ype viruses and to establish the phylogenetic relationship between mumps virus strains. Mumps RNA was directly detected in clinical specimens by PCR using primers for the small hydrophobic (SH)...