A Small Iridescent Virus (Type 29) Isolated from Tenebrio molitor: a Comparison of its Proteins and Antigens with Six Other Iridescent Viruses

Abstract

SUMMARYA small iridescent virus (type 29) has been isolated from the meal worm Tenebrio molitor. The virus is distinct from a number of previous isolates of small iridescent viruses (types 2, 6, 21, 22, 23 and 28) judged by polyacrylamide gel electrophoresis of its structural polypeptides. Immunodiffusion and immunoprecipitation tests showed that iridescent virus type 29 is related to types 22 and 23 but not types 2, 6, 21 and 28. The relationships between iridescent virus types 22, 23 and 29 were further studied by complement fixation and kinetic neutralization. Complement fixation tests confirmed that these viruses were related and showed that type 29 is distantly related to types 22 and 23 (which were more closely related to each other) though type 23 shares a closer relationship with type 29 than type 22. Kinetic neutralization experiments suggested a close relationship between types 29 and 23, and that both these viruses were remotely related to type 22. Low neutralization rate constants were obtained with these sera.

Proposals for a new classification of iridescent viruses

“…The majority of the IVs fell into two interrelated groups, with mosquito and isopod IV1 IV2 IV3 IV6 IV9 IV10 IV18 IV21 IV22 IV24 1V28 1V29 IV30 IV31 FV3 FLCDV IVs appearing distinct and separate in addition to the vertebrate viruses. This is in broad agreement with the serological studies summarized by Kelly et al (1979) in which one main serogroup comprised IV1, IV2, IV9, IV10, IV16, IV18, IV21, IV22, IV23, IV25 and IV28. IV6 and IV24 were described as serologically distinct from other isolates and from each other.…”

“…In agreement with the serological studies summarized in Kelly et al (1979), Chilo IV (IV6) appeared distantly related to most of the other members of the Iridovirus genus with the exception of IV21 and IV28. Recently, Stohwasser et al (1993) have used oligonucleotide primers representing conserved regions of the IV1 and IV22 MSP gene sequences (Tajbakhsh et al, 1990;Cameron, 1990) for PCR amplification and identification of the MSP gene of IV6.…”

“…The gene showed a DNA sequence similarity of 66.1% when compared to the gene from IV1. A noticeable difference in the characterization of IV6 compared to the serological summary of Kelly et al (1979) was detected in its relationship to IV21 and IV28. IV21 (Helicoverpa armigera IV) and IV28 (Lethocerus columbiae IV) have been acknowledged to be virtually indistinguishable from one another serologically since they were first described (Carey et al, 1978), and were assigned to the main serogroup of related viruses which included IV1, IV2 and IV22, but not IV6.…”

“…IV1 belongs to the largest group of inter-related isolates. IV2 (Sericesthis IV) has often been used in comparative studies with IVs that have been discovered subsequently (Bellet & Fenner, 1968;Glitz et al, 1968;Kalmakoff et al, 1972;Kelly & Avery, 1974;Elliott et aI., 1977;Kelly et al, 1979;Moore & Kelly, 1980). IV1 and IV2 have been described as strains of the same virus (Glitz et al, 1968;Willis, 1990).…”

“…According to the serological grouping of Kelly et al (1979), IV24 (Apis IV) is unrelated to any of the other invertebrate IVs. However genomic analyses indicated that this was not the case.…”