Molecular Characterization of msp2/p44 of Anaplasma phagocytophilum Isolated from Infected Patients and Haemaphysalis longicornis in Laizhou Bay, Shandong Province, China

Abstract

Molecular characterization of the MSP2/P44 protein of Anaplasma phagocytophilum may determine not only if the bacterium is capable of invading hosts but also whether it generates antigenic variation for the purpose of escaping the host immune response, resulting in various pathologic injuries and serious clinical outcomes. Chinese anaplasmosis patients usually present with serious manifestations, and the fatality rate is as high as 26.5%. In this study, we amplified, cloned and sequenced the msp2/p44 genes of three Chinese A. phagocytophilum isolates from Laizhou Bay, Shandong Province, where human granulocytic anaplasmosis (HGA) patients present severe clinical manifestations, and analyzed their genetic characterization and structural features. We also compared them with the HZ and Webster A. phagocytophilum strains. The sequences for both strains are available in GenBank. Analyses indicated that Chinese A. phagocytophilum isolates were significantly different from the HZ and Webster strains in terms of nucleotide sequences, amino acid sequences and protein secondary and tertiary structures. Moreover, the number of immunologic B-cell epitopes (19) of the MSP2 protein of the Chinese isolates was higher than that of the A. phagocytophilum strains HZ (16) and Webster (9). This genetic diversity of the MSP2/P44 protein of Chinese A. phagocytophilum isolates might be relevant and might have serious clinical outcomes. This observation could provide a clue to further understand the pathogenesis of Chinese A. phagocytophilum.

Novel variants of the newly emerged Anaplasma capra from Korean water deer (Hydropotes inermis argyropus) in South Korea

“…Consistent with our results, sequence variation at the studied gene markers has been reported previously among isolates from ticks, sheep and goats [12,[15][16][17][18][20][21][22][23][24][25]. Similarly, genetic variation is common in other Anaplasma species [40][41][42][43][44][45]. Although genetic diversity is reportedly related to infectivity, virulence, pathogenicity, niche preference, immune evasion, and/or host adaptability [46][47][48][49], this has not been established in A. capra and further studies are needed to evaluate these relationships.…”

Analysis of epidemiological characteristics of four natural-focal diseases in Shandong Province, China in 2009-2017: A descriptive analysis

“…First, HGA was still not recognized by many Chinese doctors at that time, which was likely to cause misdiagnosis or delayed antibiotic therapy [47, 48]. Second, the outer membrane protein msp2/p44 as important virulence factors of AP pathogens, and their molecular characteristics are significantly different in strains isolated from China and the United States at the nucleic acid, amino acid, and protein levels [49]. Therefore, Chinese patients often showed more serious clinical manifestations and a higher mortality rate [49].…”

Analysis on epidemiological characteristics of 4 species natural-focal diseases in Shandong Province, China in 2009-2017: a descriptive analysis

“…First, at present, HGA still not recognized by many Chinese doctors, which is likely to cause misdiagnosis and delayed antibiotic therapy[46, 47]. Second, the outer membrane protein msp2/p44 as important virulence factors of AP pathogens, and their molecular characteristics are significantly different in strains isolated from China and the United States at the nucleic acid, amino acid and protein levels [48]. Therefore, Chinese patients often show more serious clinical manifestations and a higher mortality rate[48].…”