Immunoglobulin M Antibody Response to Measles Virus Following Natural Virus Infection, Primary Vaccination, and Reexposure to the Virus

Abstract

Evaluation of the measles virus ELISA kit (Merck) to detect specific IgM as an indicator of primary measles antibody response was carried out. A modification of the manufacturer's cutoff value interpretation was introduced to allow for equivocal results in addition to positive and negative ones. With this modification, the test assayed gave an overall reproducibility of 96.16%. The IgM seropositivity rate for seroneutralization-confirmed measles cases was 100% for naturally infected measles subjects and 90% for primary measles vaccinated subjects. Individuals with positive neutralizing antimeasles antibodies in close contact with a confirmed measles case gave the following measles IgM ELISA results: 54.54% negative, 9.09% positive, and 36.36% equivocal, showing a booster with IgM antibody response on reexposure to the virus. Positive subjects with neutralizing antimeasles antibodies without recent contact with a measles case gave negative IgM results. IgM seropositivity was strongly associated with IgG seroconversion and clinical measles (p < 0.0001). The technique assayed performed adequately for the confirmation of both measles natural infection and primary vaccination and for the differentiation of primary and secondary antibody response, taking into account the modification in the cutoff value interpretation introduced and providing that the serum samples are obtained between days 5 and 30 after onset of rash.

Assessment of Immunoglobulin M Enzyme Immunoassays for Diagnosis of Measles

“…1). For the Meddens and Denka Seiken EIAs, sensitivity increased when the sample was collected Ͼ3 days after rash onset, as has been shown for the development of the IgM response to measles virus for both vaccinated and naturally infected individuals (7,9,13). However, the sensitivity of the Behring assay was essentially the same for samples collected before and after 3 days post-rash onset.…”

Low titers of measles antibody in mothers whose infants suffered from measles before eligible age for measles vaccination

“…Thus, we tested measles IgM in all 24 mothers; 6 of them were positive with the OD450 values ranging from 0.302-0.621 (Table 1). Infection of measles virus in persons with the history of vaccination may have detectable IgM [8,9]. Compared with the high concentrations of measles IgG in their sera (Table 1), the relatively low OD450 values (0.302-0.621) of the specific IgM in the ELISA test strongly suggest that these 6 mothers were exposed to the virus in the presence of pre-existing measles IgG, rather than the primary infection in the absence of immunity, because the ratio of IgM to IgG after re-exposure, if IgM is detected, is lower than the ratio in previously unexposed persons [8].…”