Protection Against West Nile Virus Induced by a Previous Injection With Dengue Virus

The mechanism of cross-protection afforded by dengue virus against West Nile virus in hamsters

“…Similar results were later reported from this laboratory (Price & Thind, 1972 Protection and serum neutralizing antibody titres Three separate experiments were carried out to determine the neutralizing antibody titres to West Nile virus after challenging with the large dose of West Nile virus. Samples were stopped after 6 days because many of the control hamsters started to die on the 7th day after challenge.…”

“…All virus types used were described in detail in the previous publication (Price & Thind, 1972). All virus pools, as whole infected mouse brains, were stored at -700 C. Freshly prepared homogenized brain suspensions in 0-75 % bovine plasma albumin in phosphate buffered saline, pH 7 4, clarified by centrifugation at 500 g for 10 min., were used for vaccination and challenge of animals.…”

“…Neutralization tests for West Nile virus antibody were carried out as described previously using the plaque reduction method (Price & Thind, 1972).…”

“…To determine the neutralizing antibody for dengue viruses the same method was used as described previously (Price & Thind, 1972 (Sather & Hammon, 1968, 1970 indicated that of the four dengue serotypes tested dengue 2 New Guinea C (NGC) isolate gave the best protection in hamsters against a subsequent challenge of West Nile virus. Similar results were later reported from this laboratory (Price & Thind, 1972 Protection and serum neutralizing antibody titres Three separate experiments were carried out to determine the neutralizing antibody titres to West Nile virus after challenging with the large dose of West Nile virus.…”

“…In a recent paper from this laboratory the mechanism of the cross-protection afforded by dengue virus against a subsequent challenge of West Nile virus was studied in hamsters and it was shown that this protective effect was not mediated by interferon or serum protective factor; furthermore, the cross-protection was not due to the mutual exclusion principle (Price & Thind, 1972). The relationship of the protective effect to the in vivo production of serum neutralizing antibody was not definitively establlshed.…”