scholarly journals Immune Response against the Exp-1 Protein of Plasmodium falciparum Results in Antibodies That Cross-React with Human T-Cell Lymphotropic Virus Type 1 Proteins

1998 ◽  
Vol 5 (5) ◽  
pp. 721-724 ◽  
Author(s):  
Kevin R. Porter ◽  
Joao Aguiar ◽  
Allen Richards ◽  
B. Sandjaya ◽  
H. Ignatias ◽  
...  

ABSTRACT To examine the role of the Plasmodium falciparum Exp-1 blood-stage protein in producing antibodies that cross-react with human T-cell lymphotropic virus type I (HTLV-I) proteins, we studied sera from Indonesian volunteers who seroconverted to malaria after transmigrating to an area where malaria is hyperendemic. Samples from Philippine volunteers, that were used in a prior study that examined malaria antibodies that cross-react with HTLV-I proteins, were also used. Eighty-three percent of the Indonesian transmigrants developed antibodies against the malaria Exp-1 protein by 6 months postmigration. Of these malaria seroconverters, 27% developed false-positive HTLV-I enzyme immunoassay (EIA) immunoreactivity, as indicated by indeterminate HTLV-I Western blot banding patterns. Five of the six Philippine samples tested were HTLV-I EIA false positive and Western blot indeterminate. When a recombinant Exp-1 protein was used in blocking experiments, the HTLV-I Western blot immunoreactivity of sera from both groups was either completely eliminated or greatly reduced. No effect on the Western blot immunoreactivity of truly HTLV-I-positive sera was seen. To determine if immunization with the recombinant Exp-1 protein could elicit the production of HTLV-I antibodies, six mice were inoculated with the recombinant protein. Following administration of three 50-μg doses of the protein, four of the six mice developed antibodies that cross-reacted with HTLV-I proteins on Western blot. These results indicate that the immune response against the malaria Exp-1 protein may result in HTLV-I-cross-reacting antibodies that can lead to false-positive EIA and indeterminant Western blotting results.

2011 ◽  
Vol 286 (36) ◽  
pp. 31092-31104 ◽  
Author(s):  
Batsukh Dorjbal ◽  
David Derse ◽  
Patricia Lloyd ◽  
Ferri Soheilian ◽  
Kunio Nagashima ◽  
...  

2015 ◽  
Vol 89 (9) ◽  
pp. 4880-4893 ◽  
Author(s):  
Jinhee Hyun ◽  
Juan Carlos Ramos ◽  
Ngoc Toomey ◽  
Siddharth Balachandran ◽  
Alfonso Lavorgna ◽  
...  

ABSTRACTHuman T-cell lymphotropic virus type I (HTLV-1) is an oncogenic retrovirus considered to be the etiological agent of adult T-cell leukemia (ATL). The viral transactivator Tax is regarded as the oncoprotein responsible for contributing toward the transformation process. Here, we demonstrate that Tax potently inhibits the activity of DEx(D/H) box helicases RIG-I and MDA5 as well as Toll-dependent TIR-domain-containing adapter-inducing interferon-β (TRIF), which function as cellular sensors or mediators of viral RNA and facilitate innate immune responses, including the production of type I IFN. Tax manifested this function by binding to the RIP homotypic interaction motif (RHIM) domains of TRIF and RIP1 to disrupt interferon regulatory factor 7 (IRF7) activity, a critical type I IFN transcription factor. These data provide further mechanistic insight into HTLV-1-mediated subversion of cellular host defense responses, which may help explain HTLV-1-related pathogenesis and oncogenesis.IMPORTANCEIt is predicted that up to 15% of all human cancers may involve virus infection. For example, human T-cell lymphotropic virus type 1 (HTLV-1) has been reported to infect up to 25 million people worldwide and is the causative agent of adult T-cell leukemia (ATL). We show here that HTLV-1 may be able to successfully infect the T cells and remain latent due to the virally encoded product Tax inhibiting a key host defense pathway. Understanding the mechanisms by which Tax subverts the immune system may lead to the development of a therapeutic treatment for HTLV-1-mediated disease.


Blood ◽  
1996 ◽  
Vol 88 (5) ◽  
pp. 1551-1560 ◽  
Author(s):  
A Cereseto ◽  
F Diella ◽  
JC Mulloy ◽  
A Cara ◽  
P Michieli ◽  
...  

Abstract Human T-cell lymphotropic/leukemia virus type I (HTLV-I) is associated with T-cell transformation both in vivo and in vitro. Although some of the mechanisms responsible for transformation remain unknown, increasing evidence supports a direct role of viral as well as dysregulated cellular proteins in transformation. We investigated the potential role of the tumor suppressor gene p53 and of the p53- regulated gene, p21waf1/cip1 (wild-type p53 activated fragment 1/cycling dependent kinases [cdks] interacting protein 1), in HTLV-I- infected T cells. We have found that the majority of HTLV-I-infected T cells have the wild-type p53 gene. However, its function in HTLV-I- transformed cells appears to be impaired, as shown by the lack of appropriate p53-mediated responses to ionizing radiation (IR). Interestingly, the expression of the p53 inducible gene, p21waf1/cip1, is elevated at the messenger ribonucleic acid and protein levels in all HTLV-I-infected T-cell lines examined as well as in Taxl-1, a human T- cell line stably expressing Tax. Additionally, Tax induces upregulation of a p21waf1/cip1 promoter-driven luciferase gene in p53 null cells, and increases p21waf1/cip1 expression in Jurkat T cells. These findings suggest that the Tax protein is at least partially responsible for the p53-independent expression of p21waf1/cip1 in HTLV-I-infected cells. Dysregulation of p53 and p21waf1/cip1 proteins regulating cell-cycle progression, may represent an important step in HTLV-I-induced T-cell transformation.


Blood ◽  
1996 ◽  
Vol 88 (5) ◽  
pp. 1551-1560 ◽  
Author(s):  
A Cereseto ◽  
F Diella ◽  
JC Mulloy ◽  
A Cara ◽  
P Michieli ◽  
...  

Human T-cell lymphotropic/leukemia virus type I (HTLV-I) is associated with T-cell transformation both in vivo and in vitro. Although some of the mechanisms responsible for transformation remain unknown, increasing evidence supports a direct role of viral as well as dysregulated cellular proteins in transformation. We investigated the potential role of the tumor suppressor gene p53 and of the p53- regulated gene, p21waf1/cip1 (wild-type p53 activated fragment 1/cycling dependent kinases [cdks] interacting protein 1), in HTLV-I- infected T cells. We have found that the majority of HTLV-I-infected T cells have the wild-type p53 gene. However, its function in HTLV-I- transformed cells appears to be impaired, as shown by the lack of appropriate p53-mediated responses to ionizing radiation (IR). Interestingly, the expression of the p53 inducible gene, p21waf1/cip1, is elevated at the messenger ribonucleic acid and protein levels in all HTLV-I-infected T-cell lines examined as well as in Taxl-1, a human T- cell line stably expressing Tax. Additionally, Tax induces upregulation of a p21waf1/cip1 promoter-driven luciferase gene in p53 null cells, and increases p21waf1/cip1 expression in Jurkat T cells. These findings suggest that the Tax protein is at least partially responsible for the p53-independent expression of p21waf1/cip1 in HTLV-I-infected cells. Dysregulation of p53 and p21waf1/cip1 proteins regulating cell-cycle progression, may represent an important step in HTLV-I-induced T-cell transformation.


1990 ◽  
Vol 11 (6) ◽  
pp. 314-318 ◽  
Author(s):  
Julie Larkin ◽  
John T. Sinnott ◽  
Joshua Weiss ◽  
Douglas A. Holt

Human T-cell lymphotropic virus type-1 (HTLV-I) is a recently recognized retrovirus identified as the cause of adult T-cell leukemia-lymphoma (ATLL) and HTLV-I-associated myelopathy (TSPI HAM). HTLV-I, a member of theRetroviridaefamily of viruses, was first described in 1980 after the isolation of the virus from a patient with a T-cell lymphoma. These pathogenic retroviruses are typically divided into theOncovirinaeandLentivirinae. The oncovirus group, including HTLV-I, HTLV-II and bovine leukemia virus (BLV), is generally associated with tumors. The lentiviruses are associated with immune deficiency and/or neurologic disease, and include agents such as the visna virus of sheep and the human immunodeficiency virus type-1 and -2 HIV-1 and HIV-2).


2006 ◽  
Vol 74 (2) ◽  
pp. 246-249 ◽  
Author(s):  
TETSUO HIRATA ◽  
NAGISA KINJO ◽  
KAZUTO KISHIMOTO ◽  
JIRO FUJITA ◽  
AKIRA HOKAMA ◽  
...  

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