Type-1 interferons prolong the lifespan of neutrophils by interfering with members of the apoptotic cascade.

Polymorphonuclear Neutrophils (PMNs) are metabolically highly active phagocytes, present in abundant numbers in the circulation. These active cells take the onus of clearing invading pathogens by crowding at inflammatory sites in huge numbers. Though PMNs are extremely short living and die upon spontaneous apoptosis, extended lifespan has been observed among those cells arrive at the inflammation sites or tackle intracellular infections or face any microbial challenges. The delay/inhibition of spontaneous apoptosis of these short-living cells at the inflammatory core rather helps in combating pathogens. Like many candidates, type-1 interferons (type-1 IFNs) is a group of cytokines predominant at the inflammation site. Although there are some isolated reports, a systematic study is still lacking which addresses the impact of the predominant type of interferon on the spontaneous apoptosis of neutrophils. Here in, we have observed that exposure of these IFNs (IFN-ß, IFN-α & IFN-ω etc) on human neutrophils prevents the degradation of the Bfl1, an important anti-apoptotic partner in the apoptotic cascade. Treatment showed a significant reduction in the release of cytochrome-C in the cytosol, a critical regulator in the intrinsic apoptotic pathway. We also noticed a reduction in the conversion of procaspase -3 to active caspase-3, a crucial executioner caspase towards initiation of apoptosis. Taken together our results show that exposure to interferon interferes with apoptotic pathways of neutrophils and thereby delay its spontaneous apoptosis. These findings would help us further deciphering specific roles if these inflammatory agents are causing any immune-metabolomic changes on PMNs at the inflammatory and infection core.

Pro-inflammatory cytokine Interleukin-1ß (IL-1ß) controls Leishmania infection.

Leishmania is an obligate intracellular parasite uses low pH phagolysosomal compartments of host macrophages as their final abode. IL-1ß is a pro inflammatory cytokine, which is secreted by immune cells to trigger inflammation and this has been found profoundly in the lesions caused by Leishmania pathogens. But the specific role of this cytokine on host cell macrophages during infection has not been fully explored. Here in, we have showed that prolonged exposure of IL-1ß on macrophages increases the parasite burden. Pre-treatment of bone marrow derived macrophages (BMDM) with IL-1ß also generates significantly higher amount of anti-inflammatory cytokine IL-10. As IL-10 plays crucial role in the establishment of infection, enhanced production of IL-10 observed upon IL-1ß treatment could contribute to the progression of the disease. By quantifying the production of Nitric oxide (NO), we further report that the pretreatment of IL-1ß fails to produce the nitric oxide. By measuring the footpad thickness in two different mice strains of differential susceptibility we showed IL-1ß treatment increases parasitic burden. As our results shows that the exposure of IL-1ß helps in disease progression, IL-1ß signalling may be an attractive target for future therapeutic intervention.

Neutrophils: Interplay between host defense, cellular metabolism and intracellular infection.

Neutrophils are short-living innate immune cells present in abundance in the circulation and they provide the first line of defense against infection. Microbicidal effector functions of the immune cells are tightly linked with their metabolic state. Overall knowledge of the association of neutrophil defense with cellular metabolism is still elusive. Recent studies have reported that neutrophil metabolism during granulopoiesis is impacted by the homeostatic process of autophagy. Autophagy is a complex process of which the subtype xenophagy, an antimicrobial autophagic process, clears invading pathogens. Neutrophils, being sentinels of innate immunity, encounter microbes and digest them. Studies on neutrophil antimicrobial autophagy process is still in its primeval state and has not been much explored as in other professional phagocytes. However, several obligate-intracellular pathogens are able to subvert the toxic antimicrobial machineries and utilize neutrophils as their final abodes or "Trojan Horses" for further propagation. In this review, we would provide an insight into the relationship between neutrophil microbicidal effector functions emphasizing on selective antimicrobial autophagy and metabolism, highlighting on some successful pathogens which have evolved ways to subvert or exploit this defense.

Contraceptive Use and Unintended Pregnancies Among HIV-Infected Women in Mumbai.

BACKGROUND: Access to reproductive health services in Human Immunodeficiency Virus (HIV) programs can greatly enhance program's potential to limit the spread of disease, reduce unintended pregnancies and safeguard the health of infected people. OBJECTIVES: To assess (i) knowledge, attitude, and use regarding contraceptives; safe sex and dual protection; (ii) fertility desires and unintended pregnancies post HIV and (iii) symptoms of reproductive tract infection/sexually transmitted infection (RTI/STI) among women infected with HIV. MATERIALS AND METHODS: A cross-sectional study among 300 currently married HIV-positive women who had not undergone permanent sterilization with no immediate desire for pregnancy. Study site was Integrated Counseling and Testing Centers (ICTC) in tertiary hospitals of Mumbai and women were interviewed using a semistructured questionnaire. RESULTS: In spite of good awareness about modern methods, 42.7 felt that contraceptives other than condoms were harmful to use due to their HIV status. Knowledge on dual protection was limited to condom (75%). Condom use increased from 5.7% pre-HIV to 71.7% post-HIV, with 89.6% reporting regular use. Future fertility desire was expressed by 8.7% women. Induced abortions post-HIV was reported by16.6% women, as pregnancies were unintended. About 69% wished to use dual contraceptive methods for effective protection if it was not harmful to be used by people living with HIV (PLHIV). CONCLUSION: Data reveals a need to promote modern contraceptive methods along with regular condom use to prevent unintended pregnancies and improve health-seeking behavior for contraception. Health system models that converge or link HIV services with other reproductive health services need to be tested to provide comprehensive reproductive healthcare to infected women in India.