Anticytomegalovirus monoclonal antibodies and processes for the in vitro diagnosis of infections by human cytomegaloviruses and a protein-kinase inducible by cytomegaloviruses and recognisable by aforesaid monoclonal antibodies

Abstract

The invention relates to a process for in vitro diagnosis of an infection by human cytomegaloviruses. The process consists of contacting cells, possibly carrying the infection, with a monoclonal antibody reacting with a polypeptide of molecular weight 68,000, induced by human cytomegalovirus and which possesses a protein-kinase activity. The detection of the reaction is preferably carried out by immunofluorescence.

1 . A process for the detection of an infection, particularly for in vitro diagnosis, by human cytomegalovirus in cells of human origin, which comprises contacting either intact cells or extracts obtained from these cells, with a monoclonal antibody defined by the combination of the following properties: 
 it gives rise to reactions detectable by aminofluorescence, on culture cells of human origin, previously infected with HCMV and fixed with acetone;    it reacts essentially with a single viral polypeptide induced by HCMV's in cells of human origin previously infected by them, this polypeptide having a molecular weight of the order of 68,000 and bearing a continuous sequential epitope, said polypeptide having the further properties of appearing in the nuclei and of then diffusing at least in part from said nuclei into the cytoplasm of said infected cells.    
     
     
         2 . The process of    claim 1    which comprises contacting said cells or cell extracts with a monoclonal antibody which is further capable of reacting with protein A.  
     
     
         3 . The process of    claim 1    wherein said monoclonal antibody is one 
 which reacts with a polypeptide which has a molecular weight of about 68,000;  
 which possesses a protein-kinase II activity;  
 which appears from 3 to 5 hours after adsorption of the virus on the cells and which, as from the time of its appearence accumulates and persists at least over 4 days in the infected cells.  
 
     
     
         4 . The process of    claim 3    which is carried out on an extract of said cells and which comprises contacting said extract with said monoclonal antibody to form a complex between said monoclonal antibody and said polypeptide, recovering said polypeptide from said complex and measuring the protein-kinase activity of said polypeptide.  
     
     
         5 . Polypeptide inducible in cells of human origin by a human cytomegalovirus and having the following characteristics: 
 it possesses a molecular weight of about 68,000;    it possesses a protein-kinase activity of the casein-kinase II type;    it is capable of causing transfer of phosphorus from ATP to casein, phosvitine, glycogen-synthetase, histones and alpha-phosphorylases;    its protein-kinase activity is inhibited by quercitine;    it is capable of being autophosphorylated in vitro;    it is thermosensitive (loss of activity at −70° C. and at 100° C.    
     
     
         6 . The polypeptide of    claim 5    which can form a complex with the monoclonal antibody of    claim 1   .  
     
     
         7 . The polypeptide of    claim 6    which can form a complex with the monoclonal antibody deposited at the C.N.C.M. under N° 1-289.  
     
     
         8 . The polypeptide of    claim 5   , whose proteinkinase activity is dependent on the presence of Mg 2+  ions, but which is dependent neither on the presence of manganese ions, nor on the presence of cAMP.  
     
     
         9 . The polypeptide of    claim 5   , which is conjugated to protein A of  Staphylococcus aureus.    
     
     
         10 . The polypeptide of    claim 6    which is in the state of a complex with said monoclonal antibody.  
     
     
         11 . A kit for diagnosis of a cellular infection by human cytomegalovirus which comprises: 
 a preparation containing monoclonal antibodies suitable for said diagnosis    control cell extracts free of infection by HCMV,    labelled antibodies directed against immunoglobulins of human blood and also capable of recognizing said monoclonal antibodies    buffers suitable for enabling a complex between HCMV infected cells or an extract of said infected cells and said monoclonal antibody to be formed and    detecting said complex when formed.