scholarly journals Suppression of DC-SIGN and gH Reveals Complex, Subset-Specific Mechanisms for KSHV Entry in Primary B Lymphocytes

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1512
Author(s):  
Nancy Palmerin ◽  
Farizeh Aalam ◽  
Romina Nabiee ◽  
Murali Muniraju ◽  
Javier Gordon Ogembo ◽  
...  

Kaposi sarcoma-associated herpesvirus (KSHV) is the causative agent of multiple cancers in immunocompromised patients including two lymphoproliferative disorders associated with KSHV infection of B lymphocytes. Despite many years of research into the pathogenesis of KSHV associated diseases, basic questions related to KSHV molecular virology remain unresolved. One such unresolved question is the cellular receptors and viral glycoproteins needed for KSHV entry into primary B lymphocytes. In this study, we assess the contributions of KSHV glycoprotein H (gH) and the cellular receptor DC-SIGN to KSHV infection in tonsil-derived B lymphocytes. Our results show that (1) neither KSHV-gH nor DC-SIGN are essential for entry into any B cell subset, (2) DC-SIGN does play a role in KSHV entry into tonsil-derived B cells, but in all B cell subtypes alternative entry mechanisms exist, (3) KSHV-gH can participate in KSHV entry into centrocytes via a DC-SIGN independent entry mechanism, and (4) in the absence of KSHV-gH, DC-SIGN is required for KSHV entry into centrocytes. Our results provide a first glimpse into the complexity of KSHV entry in the lymphocyte compartment and highlight that multiple subset-dependent entry mechanisms are employed by KSHV which depend upon multiple cellular receptors and multiple KSHV glycoproteins.

2020 ◽  
Author(s):  
Farizeh Aalam ◽  
Romina Nabiee ◽  
Jesus Ramirez Castano ◽  
Jennifer E. Totonchy

AbstractDespite 25 years of research, the basic virology of Kaposi Sarcoma Herpesviruses (KSHV) in B lymphocytes remains poorly understood. This study seeks to fill critical gaps in our understanding by characterizing the B lymphocyte lineage-specific tropism of KSHV. Here, we use lymphocytes derived from 40 human tonsil specimens to determine the B lymphocyte lineages targeted by KSHV early during de novo infection in our ex vivo model system. We characterize the immunological diversity of our tonsil specimens and determine that overall susceptibility of tonsil lymphocytes to KSHV infection varies substantially between donors. We demonstrate that a variety of B lymphocyte subtypes are susceptible to KSHV infection and identify CD138+ plasma cells as a rare, but highly targeted cell type for de novo KSHV infection. Finally, we determine that the host immunological status influences the course of de novo infection in B lymphocytes. These results improve our understanding of KSHV transmission and the biology of early KSHV infection in a naïve human host, and lay a foundation for further characterization of KSHV molecular virology in B lymphocyte lineages.


1983 ◽  
Vol 158 (3) ◽  
pp. 920-931 ◽  
Author(s):  
M H Nahm ◽  
J W Paslay ◽  
J M Davie

The immunodeficiency in CBA/N mice is reflected by abnormal development of a subset of B lymphocytes. However, it is not clear how xid, the mutant gene in CBA/N mice, affects the development of this subset. Specifically, it is not known if the xid gene influences the development of the B cell subset directly or indirectly by providing the improper developmental milieu through effects on other cells. We investigated this question using female mice heterozygous for two x chromosomal genes, xid and Pgk-1 (phosphoglycerate kinase-1). Since females are mosaic because of x chromosome inactivation, their lymphocytes can be studied for the choice of the x chromosome, using the two PGK-1 isoenzymes as the cytological marker. We find that B lymphocytes in the spleen prefer the x chromosome without xid while the remaining splenocytes and cells from other tissues do not. This suggests that xid affects B lymphocytes directly and not through their developmental milieu. Furthermore, our data suggest that the precursors for IgG1- and IgG3-producing cells may be both few and different.


Author(s):  
Farizeh Aalam ◽  
Jennifer Totonchy

The incidence of Kaposi’s sarcoma-associated herpesvirus (KSHV)-associated Kaposi Sarcoma has declined precipitously in the present era of effective HIV treatment. However, KSHV-associated lymphoproliferative disorders although rare, have not seen a similar decline. Lymphoma is now a leading cause of death in people living with HIV (PLWH), indicating that the immune reconstitution provided by antiretroviral therapy is not sufficient to fully correct the lymphomagenic immune dysregulation perpetrated by HIV infection. As such, novel insights into the mechanisms of KSHV-mediated pathogenesis in the immune compartment are urgently needed in order to develop novel therapeutics aimed at prevention and treatment of KSHV-associated lymphoproliferations. In this review, we will discuss our current understanding of KSHV molecular virology in the lymphocyte compartment, concentrating on studies which explore mechanisms unique to infection in B lymphocytes.


Blood ◽  
1991 ◽  
Vol 78 (6) ◽  
pp. 1503-1515 ◽  
Author(s):  
G Inghirami ◽  
DR Foitl ◽  
A Sabichi ◽  
BY Zhu ◽  
DM Knowles

Abstract Monoclonal antibodies (MoAbs) specific for autoantibody associated cross-reactive idiotypes (CRIs) frequently recognize the Igs of neoplastic B cells in patients with chronic lymphocytic leukemia (CLL) and/or Waldenstrom's macroglobulinemia. Very little is known regarding the normal B cells expressing CRIs (CRI-positive B cells). Using a variety of MoAbs against CRIs we investigated the distribution and topographic localization of CRI-positive B cells in normal adult human lymphoid tissues. We found that CRI-positive B cells represent a significant B-cell subpopulation expressing surface IgM (greater than 90%), IgG (approximately 5%), or IgA (approximately 2%). CRI-positive B cells are homogeneously distributed throughout all lymphoid tissues, accounting for 10% to 15% of all B lymphocytes, with the exception of the thymus, in which they represent the predominant B cell population. Immunophenotypic studies showed (1) that a small subpopulation (3.7% +/- 0.8%) of CRI-positive B cells are activated in vivo, based on CD25 and CD38 antigen expression; and (2) that approximately 50% of CRI-positive B cells express the 67-Kd pan-T-lymphocyte CD5 antigen, suggesting that the CRI-positive B-cell subset and the recently described CD5-positive B-cell subset are closely related. This hypothesis is supported by the fact that CRI-positive B cells produce oligo or polyreactive Igs, which are a characteristic feature of CD5-positive B cells, and also by the fact that both B-cell subpopulations appear to use similar and restricted Ig VH gene family members.


Blood ◽  
1991 ◽  
Vol 78 (6) ◽  
pp. 1503-1515
Author(s):  
G Inghirami ◽  
DR Foitl ◽  
A Sabichi ◽  
BY Zhu ◽  
DM Knowles

Monoclonal antibodies (MoAbs) specific for autoantibody associated cross-reactive idiotypes (CRIs) frequently recognize the Igs of neoplastic B cells in patients with chronic lymphocytic leukemia (CLL) and/or Waldenstrom's macroglobulinemia. Very little is known regarding the normal B cells expressing CRIs (CRI-positive B cells). Using a variety of MoAbs against CRIs we investigated the distribution and topographic localization of CRI-positive B cells in normal adult human lymphoid tissues. We found that CRI-positive B cells represent a significant B-cell subpopulation expressing surface IgM (greater than 90%), IgG (approximately 5%), or IgA (approximately 2%). CRI-positive B cells are homogeneously distributed throughout all lymphoid tissues, accounting for 10% to 15% of all B lymphocytes, with the exception of the thymus, in which they represent the predominant B cell population. Immunophenotypic studies showed (1) that a small subpopulation (3.7% +/- 0.8%) of CRI-positive B cells are activated in vivo, based on CD25 and CD38 antigen expression; and (2) that approximately 50% of CRI-positive B cells express the 67-Kd pan-T-lymphocyte CD5 antigen, suggesting that the CRI-positive B-cell subset and the recently described CD5-positive B-cell subset are closely related. This hypothesis is supported by the fact that CRI-positive B cells produce oligo or polyreactive Igs, which are a characteristic feature of CD5-positive B cells, and also by the fact that both B-cell subpopulations appear to use similar and restricted Ig VH gene family members.


2019 ◽  
Vol 93 (16) ◽  
Author(s):  
Murali Muniraju ◽  
Lorraine Z. Mutsvunguma ◽  
Joslyn Foley ◽  
Gabriela M. Escalante ◽  
Esther Rodriguez ◽  
...  

ABSTRACTKaposi sarcoma-associated herpesvirus (KSHV) is an emerging pathogen and is the causative infectious agent of Kaposi sarcoma and two malignancies of B cell origin. To date, there is no licensed KSHV vaccine. Development of an effective vaccine against KSHV continues to be limited by a poor understanding of how the virus initiates acute primary infectionin vivoin diverse human cell types. The role of glycoprotein H (gH) in herpesvirus entry mechanisms remains largely unresolved. To characterize the requirement for KSHV gH in the viral life cycle and in determination of cell tropism, we generated and characterized a mutant KSHV in which expression of gH was abrogated. Using a bacterial artificial chromosome containing a complete recombinant KSHV genome and recombinant DNA technology, we inserted stop codons into the gH coding region. We used electron microscopy to reveal that the gH-null mutant virus assembled and exited from cells normally, compared to wild-type virus. Using purified virions, we assessed infectivity of the gH-null mutant in diverse mammalian cell typesin vitro. Unlike wild-type virus or a gH-containing revertant, the gH-null mutant was unable to infect any of the epithelial, endothelial, or fibroblast cell types tested. However, its ability to infect B cells was equivocal and remains to be investigatedin vivodue to generally poor infectivityin vitro. Together, these results suggest that gH is critical for KSHV infection of highly permissive cell types, including epithelial, endothelial, and fibroblast cells.IMPORTANCEAll homologues of herpesvirus gH studied to date have been implicated in playing an essential role in viral infection of diverse permissive cell types. However, the role of gH in the mechanism of KSHV infection remains largely unresolved. In this study, we generated a gH-null mutant KSHV and provided evidence that deficiency of gH expression did not affect viral particle assembly or egress. Using the gH-null mutant, we showed that gH was indispensable for KSHV infection of epithelial, endothelial, and fibroblast cellsin vitro. This suggests that gH is an important target for the development of a KSHV prophylactic vaccine to prevent initial viral infection.


Blood ◽  
1987 ◽  
Vol 69 (3) ◽  
pp. 919-923 ◽  
Author(s):  
M Wrightham ◽  
AL Tutt ◽  
MJ Glennie ◽  
TJ Hamblin ◽  
GT Stevenson ◽  
...  

Abstract Tumor cells from patients with B cell neoplasms often secrete small amounts of free monoclonal light chains that can be found in the urine. Such tumor-derived light chains of the lambda type from a patient with typical chronic lymphocytic leukemia have been used to raise mouse monoclonal antibodies (MoAbs). A hybridoma-secreting antibody that recognized the idiotypic lambda chain but not normal lambda chains by a preliminary screen but which also reacted with idiotypic IgM from the patient's tumor cells was selected. This MoAb in fact recognized 1 in 20 X 10(3) molecules of pooled normal lambda chains, thus establishing its specificity for a private idiotypic determinant. It failed to give a detectable reaction with normal IgM, normal serum, or a panel of IgM paraproteins. The antibody bound to the patient's neoplastic B cells but not to normal tonsillar cells. The site of binding of the antibody to idiotypic IgM is clearly separate from that of another MoAb specific for idiotypic determinants on heavy plus light chains, since the two showed additive binding curves. The determinant also appeared to be less available in dimeric lambda chains than in monomeric lambda chains or in idiotypic IgM. Antibodies to idiotypic determinants on light chains show some technical advantages and should be useful for monitoring and possibly treating B cell tumors, either alone or together with the more conventional anti-idiotypic antibodies that usually recognize the heavy and light chain combination.


2015 ◽  
Vol 99 (9) ◽  
pp. 1817-1828 ◽  
Author(s):  
Girdhari Lal ◽  
Yumi Nakayama ◽  
Apoorva Sethi ◽  
Amit K. Singh ◽  
Bryna E. Burrell ◽  
...  

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