Comparison Of The Raji Cell Line Fluorescent Antibody To Membrane Antigen Test And The Enzyme-Linked Immunosorbent Assay For Determination Of Immunity To Varicella-Zoster Virus

Vol. 16, No. 5

JOURNAL OF CLINICAL MICROBIOLOGY, Nov. 1982, p. 878-884

0095-1137/82/110878-07$02.00/0
Copyright © 1982, American Society for Microbiology

Comparison of the Raji Cell Line Fluorescent Antibody to
Membrane Antigen Test and the Enzyme-Linked
Immunosorbent Assay for Determination of Immunity to
Varicella-Zoster Virus
JEFFREY P. ILTIS,l* GABRIEL A. CASTELLANO,' PAULGERBER,2t CHINH LE 3 LUBA K.
VUJCIC,2 AND GERALD V. QUINNAN, JR.2
Microbiological Associates, Bethesda, Maryland 208161; Bureau of Biologics, Bethesda, Maryland 202052;
and Department of Pediatrics, Kaiser Foundation Health Plan, Sacramento, California 958253
Received 1 April 1982/Accepted 25 June 1982

A prospective study was performed comparing the fluorescent antibody to
membrane antigen(FAMA) test and the enzyme-linked immunosorbent assay
(ELISA) for identifying susceptibility and seroconversion to varicella-zoster virus
(VZV) infection. A total of 75 sera were collected from index cases and from
sibling and parent contacts in 10 families. Varicella-zoster virus-infected human
diploid embryonic fibroblasts and continuous lymphoblastoid cells (Raji cells)
were compared asindicator cells in the FAMA test. Equivalent results were
obtained with both types of cell. Results of the FAMA test and the ELISA were
identical in two ways. (i) The same 11 individuals were initally defined as
susceptible (seronegative), and 9 of them (82%) developed fourfold rises in
antibody titers, clinical varicella, or both. (ii) Of 21 immune (seropositive)
individuals, 4 developed fourfoldantibody rises by FAMA tests, and 3 of these 4
responded by ELISA. Infection was asymptomatic in these individuals. The
geometric mean titer by ELISA was significantly higher than by the FAMA test.
The results indicated that the ELISA and the FAMA test have similar capacities
to define susceptibility to varicella-zoster virus and that subclinical infection with
varicella-zoster virus may becommon.

The fluorescent antibody to membrane antigen (FAMA) assay for detecting immunoglobulin G (IgG) antibody to varicella-zoster virus
(VZV) was first described by Williams et al. (11)
in 1974. It soon became apparent that the FAMA
was a notable advance in the serodiagnosis of
VZV infections since it reliably differentiated
susceptible and immune individuals and was
specific even atvery low serum dilutions (5, 10,
12). The test has since become a preferred
method for definitive serodiagnosis of VZV infection. More recently, the enzyme-linked immunosorbent assay (ELISA) has also been
shown to be equal to or better than such standard assays as complement fixation, neutralization, and immune adherence hemagglutination
for detecting IgG antibodies to VZV (3). The
FAMA test andthe ELISA have been directly
compared in only one previous study, by Shanley et al. (8). In that study, the FAMA test and
the ELISA were comparable in specificity but
not in sensitivity. For reasons related to cost,
ease and rapidity of performance, and broader
t Deceased.

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utilization, it is desirable for equivalent tests for
serodiagnosis of VZV infection to be defined.
Incomparison with most cell types, human
diploid embryo fibroblasts (HDEF) are highly
susceptible to VZV infection and are the cell
type most often used in FAMA tests. LevontonKriss and co-workers (7) have shown that VZV
can infect the continuous lymphoblastoid cell
line, Raji. Moreover, they demonstrated VZV
antigen in the membranes of infected Raji cells
by indirect immunofluorescence. In thisstudy,
we evaluated the FAMA test with VZV-infected
Raji cells and the ELISA in comparison with the
standard FAMA test with fibroblast cells for
defining susceptibility to infection with VZV.
Our results indicated that VZV-infected Raji
cells were an equivalent substitute for HDEF
cells in the FAMA test. Also we report that our
ELISA was as sensitive and specific as the
FAMA test for the...