Leishmania species: A narrative review on surface proteins with structural aspects involved in host–pathogen interaction

In tropical and subtropical regions of the world, leishmaniasis is endemic and causes a range of clinical symptoms in people, from severe tegumentary forms (such as cutaneous, mucocutaneous, and diffuse leishmaniasis) to lethal visceral forms. The protozoan parasite of the genus Leishmania causes leishmaniasis, which is still a significant public health issue, according to the World Health Organization 2022. The public's worry about the neglected tropical disease is growing as new foci of the illness arise, which are exacerbated by alterations in behavior, changes in the environment, and an enlarged range of sand fly vectors. Leishmania research has advanced significantly during the past three decades in a few different avenues. Despite several studies on Leishmania, many issues, such as illness control, parasite resistance, parasite clearance, etc., remain unresolved. The key virulence variables that play a role in the pathogenicity-host-pathogen relationship of the parasite are comprehensively discussed in this paper. The important Leishmania virulence factors, such as Kinetoplastid Membrane Protein–11 (KMP-11), Leishmanolysin (GP63), Proteophosphoglycan (PPG), Lipophosphoglycan (LPG), Glycosylinositol Phospholipids (GIPL), and others, have an impact on the pathophysiology of the disease and enable the parasite to spread the infection. Leishmania infection may arise from virulence factors; they are treatable with medications or vaccinations more promptly and might greatly shorten the duration of treatment. Additionally, our research sought to present a modeled structure of a few putative virulence factors that might aid in the development of new chemotherapeutic approaches for the treatment of leishmaniasis. The predicted virulence protein's structure is utilized to design novel drugs, therapeutic targets, and immunizations for considerable advantage from a higher understanding of the host immune response.     

1例蠊缨滴虫感染报告

蠊缨滴虫感染在门诊感染中少见,易被忽略。本文通过对1例感染者的就诊过程作一详细描述,供临床医师借鉴。患者,男,62岁。长住连云港赣榆区打工。患者于2020年9月15日淋雨劳累后出现发热,咳痰,自行服药,热退。3 d后再次发热,并伴右侧胁肋部疼痛,遂至赣榆区人民医院就诊。该院检查WBC 19.74×10⁹/L,N 83.7%,超敏C反应蛋白33.19 mg/L;CT示右肺中叶及两下肺叶炎症,右侧胸腔积液。该院给予抗感染及化痰治疗共3 d,效果欠佳。22日转至江苏省中医院,血液示超敏C反应蛋白65.8 mg/L,WBC 11.66×10⁹/L,E 6.9%。CT示两肺多发结节及片状影。肺功能示肺通气功能减退。纤支镜洗液检查示存在感染。同时将纤支镜洗液送南京市疾控中心作寄生虫学相关检查。该院考虑患者肺炎,给予抗真菌及化痰治疗3 d,效果不明显。此时南京市疾控中心反馈寄生虫检测结果示蠊缨滴虫阳性。该院遂加用奥硝唑治疗,一周后患者发热、咳嗽、胸痛等症状消失,相关感染指标均恢复正常,痊愈出院。患者在两家医院以临床医生的经验先后使用抗生素治疗,效果不明显。在确定是蠊缨滴虫（同时还应注意与支气管纤毛柱状上皮细胞相鉴别）后,及时采用奥硝唑治疗,效果显著,症状很快消失。提示临床医生找对病原采用针对性治疗非常重要,蠊缨滴虫在临床感染的患者中少见,又缺乏检测手段,更易漏诊,须警惕。     

Evaluation of transmission-blocking potential of Pv22 using clinical Plasmodium vivax infections and transgenic Plasmodium berghei

Antigens expressed during the sexual development of malaria parasites are transmission-blocking vaccine (TBV) targets. Pb22, a protein expressed and localized to the plasma membrane of gametes and ookinetes in Plasmodium berghei, is an excellent TBV candidate. Here, we evaluated the TB potential of the Plasmodium vivax ortholog Pv22 using a transgenic P. berghei parasite line and P. vivax clinical isolates. The full-length recombinant Pv22 (rPv22) protein was produced and used to immunize mice and rabbits to obtain antibodies. We generated a transgenic P. berghei line (TrPv22Pb) by inserting the pv22 gene into the pb22 locus and showed that Pv22 expression completely rescued the defects in male gametogenesis of the pb22 deletion parasite. Since Pv22 in the transgenic parasite showed similar expression and localization patterns to Pb22, we used the TrPv22Pb parasite as a surrogate to evaluate the TB potential of Pv22. In mosquito feeding assays, mosquitoes feeding on rPv22-immunized mice infected with TrPv22Pb parasites showed a 49.3–53.3 % reduction in the oocyst density compared to the control group. In vitro assays showed that the rPv22 immune sera significantly inhibited exflagellation and ookinete formation of the TrPv22Pb parasites. In a direct membrane feeding assay using three clinical P. vivax isolates, the rabbit anti-rPv22 antibodies also significantly decreased the oocyst density by 53.7, 30.2, and 26.2 %, respectively. This study demonstrated the feasibility of using transgenic P. berghei parasites expressing P. vivax antigens as a potential tool to evaluate TBV candidates. However, the much weaker TB activity of Pv22 obtained from two complementary assays suggest that Pv22 may not be a promising TBV candidate for P. vivax.