April 11, 2017

Research- Department of Infection and Immunology

Current Research at the Department of Infection and Immunology


A) Immune response against Human Immunodeficiency Virus infection

Aim: Understanding the humoral and cell-mediated immune response against the Human Immunodeficiency Virus infection.

Principal Investigator: Anurag Adhikari

Details on the humoral immunity are explained in the KaVA-Program [see  https://kribs.org.np/kava-program/ ]


Recent findings and ongoing research in HIV cell-mediated immune response

Within the HIV cell-mediated study, we have optimized the peripheral blood mononuclear cells (PBMC) isolation and long-term liquid nitrogen-based cryopreservation at our laboratory. These isolated and stored PBMCs from HIV-infected individuals and controls have been documented for their pre-long term storage absolute cell count and viability (Figure 1 A-B).

[UNPUBLISHED WORK] Figure 1 A-B. Venous blood isolated peripheral blood mononuclear cell (PBMC) count between the HIV infected individuals (n=24) and the healthy individuals as control (n=6) before the cryopreservation. The graph shows the (A) absolute total cell count in millions per ml of venous blood for HIV-infected individuals and healthy controls (student t-test: P-value 0.0094) and (B) PBMC viability percentage between HIV-infected individuals and healthy controls (student t-test: P-value 0.577).

















B) Orientia tsutsugamushi infection and associated immune response in human

Principal Investigator: Anurag Adhikari

Initial results and outcomes: Summary (Unpublished paper, under preparation)

Phylogenetic analysis of the partial genome of Orientia tsutsugamushi 47kDa gene (GenBank accession: OL770337-OL770352) showed a close genetic relation with Karp-UK strain (among the 87.5% of the patients), as well with CRF93-Thailand strain (6.25% of the patients), and Karp-Thailand strain (6.25% of the patients). Similarly, phylogenetic analysis of Orientia tsutsugamushi 56kDa gene (GenBank accession: OL770323-OL770336) showed close relation with Gilliam-Bangladesh strain (among the 35.7% of the patients), Karp-Bangladesh strain (28.6% of the patients), Gilliam-UK strain (14.3% of the patients), Shimokoshi-Taiwan strain (14.3% of the patients), and with Vietnam strain (7.14% of the patients). We also show that the patient-derived groEL gene of Anaplasma (GenBank accession: OL770355 -OL770356) was closely related to the D-GB-gro-8-South Korea strain (5.5% of typhus suspected patients), and the rpoB gene of Leptospira (GenBank accession: OL770353-OL770354) was closely related to Linhai 56609-China strain (5.5% of typhus suspected patients).

This study shows that the Karp, Gilliam, and Shimokoshi strains of Orientia tsutsugamushi are circulating in southwest Nepal. Additionally, this study identifies the co-presence of Anaplasma, and Leptospira in the febrile symptomatic patient. Further genotype and serotype screening study for these bacteria among febrile patients is a current need so as to identify the tick-borne bacterial diversity and its associated disease burden among the Nepalese population.


GenBank sequence link

Orientia tsutsugamushi 47kDa gene (GenBank accession of 16 sequences: OL770337-OL770352)



Orientia tsutsugamushi 56kDa gene (GenBank accession of 14 sequences: OL770323-OL770336)



Anaplasma, (GenBank accession of 2 sequences: OL770355 -OL770356)



Leptospira, (GenBank accession of 2 sequences: OL770353-OL770354)