Cloning of aMycobacterium tuberculosisGene Encoding a Purifed Protein Derivative Protein That Elicits Strong Tuberculosis‐Specific Delayed‐Type Hypersensitivity

Abstract

The purified protein derivative (PPD) skin test has been used for the diagnosis of tuberculosis for more than 75 years. However, the test lacks specificity because all mycobacteria share antigens present in PPD. Therefore, sensitization with nontuberculous pathogenic or with environmental nonpathogenic mycobacteria can lead to positive skin tests. This communication describes a novel PPD protein present only in tuberculous complex mycobacteria. A recombinant protein was obtained and named DPPD on the basis of the first 4 amino acids of its N-terminus sequence. DPPD elicited delayed-type hypersensitivity (DTH) in 100% of Mycobacterium tuberculosis-infected guinea pigs but in no animals sensitized with several organisms representative of all members of the Mycobacterium genus. Preliminary results indicate that DPPD induces strong and specific DTH in humans. This work points to the definition of a single recombinant M. tuberculosis protein that may be an alternative to the PPD test.

Potential Serological Use of a Recombinant Protein That Is a Replica of aMycobacterium tuberculosisProtein Found in the Urine of Infected Mice

“…Nevertheless, this test lacks specificity for Mycobacterium tuberculosis (2,21) and requires special medical or paramedical personnel to perform it and read the results. However, the replacement of the native multiantigenic preparation used in the Mantoux test (purified protein derivative of tuberculin [PPD]) by purified recombinant proteins has recently been reported to successfully improve the specificity of this test (5,9).…”

Three Protein Cocktails Mediate Delayed-Type Hypersensitivity Responses Indistinguishable from That Elicited by Purified Protein Derivative in the Guinea Pig Model ofMycobacterium tuberculosisInfection

“…Many protein candidates have been described as tuberculosis-specific skin test antigens over the past 2 decades (5,6,11,24); however, none have reached an optimal diagnostic sensitivity. In this study, the protein mixtures described elicited a response that was equal to or greater than the response to PPD and was indistinguishable from PPD at the molecular level.…”

“…Some protein candidates, including ESAT-6 (28), CFP10 (39), MPT64 (24), DPPD (6), and Rv0934 (17), were tested and found to induce strong DTH reactions in guinea pigs, but none of them were developed as secondgeneration skin test reagents. Several studies indicate that a combination of several purified antigens (antigen cocktails) or a combination of several DTH-inducing epitopes may be required for second-generation skin test reagents to effectively replace PPD (21,24,32).…”

Evaluation of Recombinant <i>Mycobacterium tuberculosis</i> Antigens MPT64, CFP10, and ESAT6 for Delayed-Type Hypersensitivity Responses in Guinea Pigs

“…Skin test responses (diameter of erythema/redness) were observed and measured after 24, 48, and 72 h. Erythema diameter greater than 0.5 cm was considered as skin test positive [3]. For ease of interpretation, the erythema formation was determined and scored as follows: 0 = absent, not perceptible; 1 = mild redness, diameter < 0.5 cm; 2 = mild redness, diameter > 0.5 cm; 3 = redness, diameter > 0.5 but < 0.8 cm; 4 = redness, diameter > 0.8 cm; and 5 = redness, diameter > 0.5 cm, papule.…”