Molecular characterization of human T‐cell lymphotropic virus type 2 (HTLV‐II) from people living in urban areas of Sao Paulo city: Evidence of multiple subtypes circulation

Abstract

Two hundred ninety-three individuals, who were enrolled in the HTLV out-clinic in Sao Paulo city, Brazil, between July 1997 and May 2003, were tested by EIAs, and positive sera 232 (79%) reactive by one of the tests. When these sera were tested by WB revealed 134 were HTLV-I, 28 HTLV-II, 4 HTLV-I/II, and 48 were indeterminate. Polymerase chain reaction (PCR) on the indeterminate group showed that 20 (42%) were HTLV-II and 28 were negative. From a total of 48 HTLV-II subjects with DNA available, restriction fragment length polymorphism (RFLP) of the env region revealed 47 HTLV-IIa and 1 HTLV-IIb. The phylogenetic analysis was performed on 23 samples, which identified 19 as subtype a, Brazilian subcluster, and 4 as subtype b. This is the first time HTLV-II subtype b has been described in Brazil. However, further studies, such as a complete nucleotide DNA sequencing, need to be done to confirm these findings.

Human T Cell Lymphotropic Virus Type 2a Strains Among HIV Type 1-Coinfected Patients from Brazil Have Originated Mostly from Brazilian Amerindians

“…19 Still, the amino acid change S1909P in 100% of the env sequences was also previously reported in Brazilian strains, and could represent a molecular signature of HTLV-2a (variant 2c) strains from Brazil. 21,29 In relation to the tax sequences, the present results corroborated the previous reports that characterize the Brazilian HTLV-2c variant (often considered a molecular variant of -2a), highlighting the long Tax protein. 7,13,15 In addition, high similarity in tax was observed among isolates from the present study (99.9%) and also in relation to the Mo prototype (99.3%).…”

“…13,15,21 The phylogenetic tree of the env region showed the presence of a group almost exclusively of IDUs, also found in the LTR and tax trees. These clades could represent a different route of virus transmission among IDUs or a little diverse evolutionary virus rate, as described in European IDUs.…”

“…7 Therefore, HTLV-2 molecular characterization worldwide disclosed four HTLV subtypes: HTLV-2a and HTLV-2b, the most prevalent among IDUs from urban areas of the Americas and Europe and in the indigenous population of the Americas, and with sporadic distribution in Asia and Africa; the HTLV-2c variant detected in the indigenous population of the Brazilian Amazon and in IDUs from urban populations in Brazil; and the HTLV-2d detected in pygmy tribes in Africa. 13,[16][17][18][19][20][21] In 2010, we started the characterization of HTLV-2 isolates that circulate in HIV-coinfected individuals from southern Brazil using nucleotide sequence and restriction fragment length polymorphism (RFLP) analysis of the LTR region, and confirmed that all HTLV-2 strains belonging to the 2a subtype. Moreover, we observed an association of molecular variants and sexual risk factor and injecting drug use.…”

Neither molecular diversity of the envelope, immunosuppression status, nor proviral load causes indeterminate HTLV western blot profiles in samples from human T‐cell lymphotropic virus type 2 (HTLV‐2)‐infected individuals

“…A total of 615 individuals had been seen in the HTLV out-clinic at Emilio Ribas from July 1997 to March 2009. Using our algorithm published previously [Novoa et al, 2007], 104 HTLV-2-infected subjects were disclosed in the last 12 years. For this study, we randomly chose 29 samples that filled the full criteria for HTLV-2 infection and 21 samples from individuals who were indeterminate WB.…”

“…Tests that used only lysate of HTLV-1 virus did not show sufficient sensitivity for detecting antibodies against HTLV-2 [Zehender et al, 1997;Waziri et al, 2000]. A recent study in our laboratory found that 50% of samples from a high-risk population identified by WB as indeterminate were HTLV-2 by PCR [Novoa et al, 2007].…”