Fixed-cell immunoperoxidase technique for the study of surface antigens induced by the coronavirus of transmissible gastroenteritis (TGEV)

Abstract

An immunoperoxidase technique performed on the TGEV-infected cells was developed for detection of virus-induced antigens. The presence of M antigen of TGEV on the surface of infected cells was demonstrated by this technique. This finding is in contrast to the M protein of murine hepatitis coronavirus which migrates to the Golgi apparatus but is not transported to the plasma membrane. The time course of appearance M and S antigens on the surface of TGEV-infected cell can be studied by this technique.

Incorporation of Spike and Membrane Glycoproteins into Coronavirus Virions

“…The IBV-M protein is localized to the cis -Golgi [ 72 , 76 ], while the MHV-M protein is localized to the trans -Golgi and the TGN [ 72 , 77 ]. In some cases, however, the TGEV-M protein [ 78 , 79 ] and the feline infectious peritonitis virus (FIPV) M protein [ 80 ] in infected cells or independently expressed epitope tagged or untagged SCoV-M protein [ 44 , 81 ] were transported to the plasma membrane. It is noteworthy that, although M proteins play an essential role in the CoV budding process, which occurs exclusively at the ERGIC, a large portion is transported to the Golgi complex or even the plasma membrane beyond the ERGIC [ 72 ].…”

Self-assembly of Severe Acute Respiratory Syndrome Coronavirus Membrane Protein

“…M is the most abundant coronavirus structural protein, with an expression level in host cells ∼100-fold greater than that of E ( 18 ). Except for M proteins in the transmissible gastroenteritis virus and feline infectious peritonitis virus, both of which are capable of reaching the plasma membrane ( 19 – 21 ), the M proteins of other coronaviruses (including SARS-CoV M) localize exclusively at the ER/Golgi area, where virus assembly and budding takes place ( 22 – 24 ). Nevertheless, it is well established that M plays a key role in directing virus assembly and determining viral budding sites ( 25 , 26 ).…”

“…Furthermore, M plasma membrane localization remains equivocal. The transmissible gastroenteritis virus M protein has been described as capable of reaching the plasma membrane ( 19 , 20 ) and of intracellular localization ( 33 ). Results from one study failed to indicate plasma membrane labeling of SARS-CoV M ( 34 ), but results from another study indicate that SARS-CoV M is detectable on cell surfaces as well as in Golgi compartments ( 35 ).…”

Development of Protection against Coronavirus Induced Diseases

“…S protein also induces protection against mv and MHY. These proteins are frequently detected in small quantities in the surface of virus infected cells associated to the presence of virions, while they are detected in the cytoplasm of infected cells in large quantities29, 35,17,48,64,82,27,58,105,43,51,70,32,89,31,20,44,102,34. These data are in agreement with the concept that coronaviruses assemble at rough endoplasmic reticulum and Golgi membranes.…”