Agar gel immunodiffusion analysis using baculovirus-expressed recombinant bovine leukemia virus envelope glycoprotein (gp51/gp30T-)

Abstract

Bovine leukemia virus (BLV) envelope glycoprotein (gp51/gp30T-), consisting of BLV gp51 and BLV gp30 that lacked its C-terminal transmembrane domain, was expressed in insect cells under the control of the baculovirus polyhedron promoter. Recombinant BLV gp51/gp30T- secreted from insect cells was determined by immunofluorescence, enzyme-linked immunosorbent and western blot assays using a BLV-specific monoclonal antibody and BLV-positive bovine antibodies. An agar gel immunodiffusion (AGID) test using gp51/gp30T- as the antigen for the detection of BLV antibodies in serum was developed and compared to traditional AGID, which uses wild type BLV antigen derived from fetal lamb kidney cells. AGID with the recombinant BLV gp51/gp30T- was relatively more sensitive than traditional AGID. When the two methods were tested with bovine sera from the field, the recombinant BLV gp51/gp30T- and traditional antigen had a relative sensitivity of 69.8% and 67.4%, respectively, and a relative specificity of 93.3% and 92.3%. These results indicated that the recombinant BLV gp51/gp30T- is an effective alternative antigen for the diagnosis of BLV infection in cattle.

Sequencing and phylogenetic analysis of the gp51 gene from Korean bovine leukemia virus isolates

“…Seven genotype 1 isolates were found in Gyeongsangbuk-do (GBGS) and 8 isolates were found in Gyeongsangnam-do (GNCN). Indeed, genotype 1 was reported in Korea in 2009 [ 24 ] and was expected to be the dominant form found in our study. Two isolates from the Gyeongsangbuk-do region were assigned to genotype 3, a result that was also seen in a recent Japanese study [ 36 ].…”

“…EBL was first reported by the serological method in Korea in the 1980s [ 19 ], and recently, its prevalence in dairy cattle was found to be over 50% [ 20 - 23 ]. To date, there has been no reports of the BLV genotype circulating in Korea since partial env gene sequences that belonged to genotype 1 were deposited in 2009 [ 24 ]. It is known that some of the genotype groupings correlate with the geographical origin of the strain [ 16 , 25 - 34 ], but with the increased movement of cattle and people around the world, a variety of genotypes have been reported in places where only a specific genotype was dominant in the past [ 17 , 33 ].…”

Epidemiology and genetic diversity of bovine leukemia virus

“…A variety of BLV genotypes (−1, −2, −4, −5, −7, and −9) were detected in South America: genotypes −1, −2, −4, and −6 in Argentina [ 93 , 95 , 97 , 147 , 148 ]; genotypes −1, −2, −5, −6, and −7 in Brazil [ 122 , 123 , 127 ]; genotypes −4 and −7 in Chile [ 94 ]; genotypes −1, −2, −6, and −9 in Bolivia [ 75 ]; genotypes −1, −2, and −6 in Peru and Paraguay [ 75 ]; and genotype-1 in Uruguay [ 126 ]. In Asia, a total of seven BLV genotypes have been confirmed (−1, −2, −3, −4, −6, −7, and −10): genotypes −1 and −3 in Korea [ 101 , 149 ]; genotypes −1, −2, and −3 in Japan [ 93 , 99 , 143 , 150 ]; genotypes −1 and −6 in The Philippines [ 74 ]; genotypes −1, −6, and −10 in Thailand [ 102 ]; genotypes −1, −4, and −7 in Mongolia [ 77 ]; genotype-10 in Myanmar [ 76 ]; and genotypes −1 and −6 in Jordan [ 151 ].…”

Genetic diversity of bovine leukemia virus worldwide

“…A total of seven BLV genotypes have been identified in samples from Asia (G-1, -2, -3, -4, -6, -7 and -10): genotype -1, -2 and -3 in Japan (Licursi et al 2003;Zhao & Buehring 2007;Matsumura et al 2011;Inoue et al 2011); genotype -1 and -3 in Korea (Lim et al 2009;Lee et al 2015); genotype -1 and -6 in The Philippines (Polat et al 2015); genotype-1, -6…”