Ribosomal protein L7 included in tuberculin purified protein derivative (PPD) is a major heat-resistant protein inducing strong delayed-type hypersensitivity.
The tuberculin purified protein derivative (PPD) is a widely used diagnostic antigen for tuberculosis. It consists of more than 100 denatured proteins in a culture filtrate of a heated culture of Mycobacterium tuberculosis. In two-dimensional electrophoretic analysis of PPDs from M. tuberculosis and M. bovis BCG, most proteins were diffusely separated and could not be seen as spots because of denaturation, whereas a few proteins showed relatively clear spots, indicating heat resistance. Two such proteins corresponded to ribosomal proteins L7 and L12. The mixture of these proteins L7/L2 induced a strong delayed-type hypersensitivity reaction. Another protein showing a clear spot was a GroES analogue, but this did not induce delayed-type hypersensitivity. There were a few other unidentified proteins. It is well known that L7 and L12 are encoded by the same gene and that they differ from each other only by an acetylic post-translational modification that occurs at the N-terminus of L12 converting it to L7 in Escherichia coli. L12, but not L7, was found in two-dimensional electrophoresis of BCG ribosomes, although we found two proteins corresponding to L7 and L12 in PPDs and a native culture filtrate of BCG. We compared the delayed-type hypersensitivity reaction elicited by L7/L12 derived from a culture filtrate of BCG and L12 derived from BCG ribosomes. L7/L12 from the culture filtrate could induce delayed-type hypersensitivity, but L12 from ribosomes could not, indicating that L7 was attributable to the induction of delayed-type hypersensitivity. The activity of L7/L12 was heat resistant. Neither glycosylation nor phosphorylation of L7/L12 from a culture filtrate could be detected. The acetylation at N-terminal of L12 was essential for the delayed-type hypersensitivity activity.
Kitaura
H
H
School of Dentistry, Nagasaki University, 1-7-1 Sakamoto, Nagasaki City 852-8588, Japan.
Kinomoto
M
M
Yamada
T
T
D000107:Acetylation; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology*; D017077:Culture Media, Conditioned; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D005260:Female; D006168:Guinea Pigs; D006358:Hot Temperature; D006968:Hypersensitivity, Delayed / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D009163:Mycobacterium bovis / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D009166:Mycobacterium leprae / Q000235:genetics / Q000276:immunology; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011489:Protein Denaturation; D011499:Protein Processing, Post-Translational; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification; D012269:Ribosomal Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D012270:Ribosomes / Q000737:chemistry; D020539:Sequence Analysis, Protein; D013045:Species Specificity; D014373:Tuberculin / Q000737:chemistry / Q000276:immunology*
D001426:Bacterial Proteins; D017077:Culture Media, Conditioned; D029968:Escherichia coli Proteins; D011993:Recombinant Fusion Proteins; D012269:Ribosomal Proteins; C512845:Rpl7 protein, mouse; D014373:Tuberculin; C512844:rplL protein, E coli; C016700:ribosomal protein L7-L12