Characterization Of Antiviral Components In Human Seminal Plasma

Background and objectives:A large number of virus types can infect the human male reproductive system and release to the semen,which raise a risk of the sexual transmission of viruses.In fact,only minor virus types in semen may be sexually transmitted.The potential effect of semen on the viral infectivity and transmission remains unclear.This thesis focuses on the antiviral effect of human seminal plasma(SP)by characteristics the antiviral components of SP against mumps virus(MuV)and herpes simplex virus type 1(HSV-1).Materials and methods:The cervical cancer cell line(HeLa)was used as the target cell for virus infection,and the African green monkey kidney cell(Vero)was used to amplify MuV and HSV-1.The titers of MuV and HSV-1 and the viral load in medium were measured by TCID50 assay.The protein levels were detected by Western blot.Real-time qRT-PCR was used to determine mRNA levels.The distribution of virus particles in cells was detected by immunofluorescence staining.Morphological changes of living cells were observed under microscope.CCK-8 assay was used to detect cell activity.In addition,epididymal epithelial cells(EECs),human cervical cancer cells(C33A)and mouse testicular epithelial cells(15P1)were used as target cells to study the effect of SP on MuV in other target cells.Results:MuV replicated effectively in HeLa cells after infection.The pre-incubation of MuV with SP abolished MuV infection.The treatment of SP with boiling H2O,proteinase K(ProK),RNase A,DNase I,peptide N glycosidase F(PNGase F)or Lipase did not impact its inhibition on MuV infection.The molecular weight of the antiviral factor in SP is between 3 and 100 kDa.HSV-1 also infected HeLa cells.HSV-1 infection of HeLa cells resulted in changes in cell morphology.The pre-treatment of HSV-1 with SP inhibited HSV-1 infection of HeLa cells.However,SP treated with boiling H2O lost its anti-HSV-1 activity.The coincubation of HSV-1 with SP could lead to the degradation of HSV-1 proteins.By contrast,SP after treatment with boiling H2O did not degrade HSV-1 proteins.The size of the antiviral factor against HSV-1 infection was more than 100 kDa.Conclusions:Human SP inhibited MuV and HSV-1 infection.The component of SP that inhibited MuV infection was heat-resistant and would not be protein,nucleic acid,lipid,or sugar.By contrast,the antiviral component against HSV-1 infection was heat-sensitive and would be a proteinase that can degrade viral proteins.These results suggest that human SP contains various antiviral components against different viruses.Further identification and isolation of the antiviral components in SP can be helpful to understand the antiviral mechanisms of the male genital system.