Japanese encephalitis vaccine-facilitated dengue virus infection-enhancement antibody in adults

BMC Infectious Diseases

Table 2 Antibody-dependent enhancement (ADE) activity against the four dengue virus (DENV) serotypes in each of the samples obtained from the 77 participants, pre- and post-Japanese encephalitis (JE) vaccination and corresponding JEV neutralizing antibody (NA) levels

ADE activity in each of the serum samples to four DENV serotypes	n	JEV NA titer^a
		(Mean JEV NA titer ± s.d.)
		Pre-vaccination	Post-vaccination
(A) Absence of ADE activity to DENV, both before and after JE vaccination	40	19 ± 29	153 ± 419
(B) Presence of ADE activity to DENV after JE vaccination only
1. ADE activity to ≥3 DENV serotypes	6	98 ± 124	1130 ± 1199
2. ADE activity to two DENV serotypes	4	91 ± 153	500 ± 592
3. ADE activity to one DENV serotype	10	47 ± 64	277 ± 372
Total	20	71 ± 101^b	578 ± 803^b
(C) Presence of ADE activity to DENV both before and after JE vaccination
1. ADE activity to ≥3 DENV serotypes	10	96 ± 122	1325 ± 1644
2. ADE activity to two DENV serotypes	1	40	80
3. ADE activity to one DENV serotype	4	53 ± 74	341 + 346
Total	15	81 ± 106^b	980 + 1422^b

^aJEV NA titers were determined by using a 50 %-focus-reduction neutralization test
^bThe increase in JEV NA levels in participants with ADE activity to DENV after JE vaccination was significantly higher in participants that demonstrated ADE after vaccination (Group B = 578 ± 803, t-test p <0.01; Group C = 980 ± 1422, t-test p < 0.01) in comparison to those that did not demonstrate ADE activity to DENV (Group A). Samples from 2 patients were excluded due to insufficient volume for the ADE assay

ISSN: 1471-2334