Josephine Clark-Curtiss

Josephine Clark-Curtiss, PhD

Professor Of Medicine

Business Phone: (352) 294-5481

About Josephine Clark-Curtiss

Dr. Clark-Curtiss initiated her research career during her Ph.D. studies at the Medical College of Georgia, Augusta, GA. She then joined the research group of Roy Curtiss III at the University of Alabama at Birmingham for postdoctoral studies, initially analyzing the genetic bases for transfer of antibiotic resistance (R) plasmids among enterobacteria. With the inception of recombinant DNA technology, she became part of the Curtiss research team that constructed and characterized the first biologically contained “safe” strains c1776 and DP50 of Escherichia coli that, for a time, were the only approved bacterial strains with which investigators throughout the US could conduct recombinant DNA research in the late 1970s. Dr. Clark-Curtiss subsequently utilized recombinant DNA techniques to conduct research on mycobacteria, beginning in the early 1980s, when she and her colleagues constructed the first recombinant DNA libraries of any mycobacterial strain, thereby initiating molecular genetics research on Mycobacterium leprae and later, on M. tuberculosis and M. avium. Dr. Clark-Curtiss and her research group were among the first to identify specific genes that encoded M. leprae proteins and they were the first to demonstrate the presence of a repeated DNA sequence in the chromosome of M. leprae (now known as Rlep, which is used for the diagnosis of leprosy). Using restriction fragment length polymorphism (RFLP) analyses of genomes from M. leprae isolates from all over the world, Dr. Clark-Curtiss showed that the M. leprae genome is remarkably stable genetically. Dr. Clark-Curtiss’ research group was the first to identify genes encoding antigens of M. leprae that were recognized by antibodies in the sera of leprosy patients.

Dr. Clark-Curtiss has a long-standing interest in understanding the mechanisms whereby pathogenic mycobacteria, particularly M. tuberculosis and M. avium, are able to survive and grow in human macrophages, an attribute essential for the pathogenesis of these bacteria. Thus, she and members of her research group developed methods to identify genes expressed by M. avium and M. tuberculosis at different time points after infection of primary human macrophages in culture. Using these methods (Subtractive RNA Hybridization and Selective Capture of Transcribed Sequences [SCOTS]), the Clark-Curtiss group was the first to identify genes from small numbers of mycobacteria in the macrophages in an unbiased way (i.e., without relying on RT-PCR using primers for specific genes), well before the development of microarray technology. In addition to gene expression per se, Dr. Clark-Curtiss has also endeavored to understand some of the mechanisms whereby M. tuberculosis regulates gene expression. During the past 10 years, the Clark-Curtiss research group has conducted studies analyzing regulation of gene expression in M. tuberculosis by four different two-component regulatory systems (TcrRS, PrrAB, DevRS and NarLS) and other transcriptional regulators (the eukaryotic serine-threonine protein kinase PknK and the M. tuberculosis Rel toxin-antitoxin modules) and deciphering the roles of these regulatory systems in host-pathogen interactions. The genes encoding the PrrAB two-component regulatory system were identified during the SCOTS analyses and were subsequently shown to essential for the viability of M. tuberculosis. The PknK serine-threonine protein kinase was shown to be a global regulator of protein synthesis and to play a significant role in regulation of the growth rate of M. tuberculosis.

In collaboration with Roy Curtiss III, the Clark-Curtiss group is developing a safe, efficacious vaccine to protect humans against infections by M. tuberculosis, using recombinant, attenuated Salmonella vaccine (RASV) strains to deliver M. tuberculosis protective antigens. The RASV strains are engineered to behave like wild type Salmonella as they traverse the mammalian gastrointestinal tract after oral inoculation, but then, using regulated delayed technologies, to begin synthesizing the antigens after the RASVs have colonized internal lymphoid tissues. The RASVs are also engineered to undergo regulated delayed lysis in vivo, to preclude long-term colonization of the immunized host and to release the synthesized antigens into the cytosol of the host cells, to elicit both humoral (antibody) and cell-mediated immune responses. Several of the RASV-M. tuberculosis constructs provide protection in mice against aerosol challenges with virulent M. tuberculosis that is equivalent to or slightly better than that conferred by M. bovis BCG, which is regarded as the “gold standard” for vaccines against M. tuberculosis. The Clark-Curtiss research group is continuing to improve the RASV and is also analyzing the protective capabilities of nine other M. tuberculosis antigens for possible incorporation into candidate RASV-M. tuberculosis constructs.


Member, National Institutes of Health Study Section ZRG1 F-13C
2010-2012 · National Institutes of Health
Member, National Institutes of Health Special Study Sections to review ARRA applications
2009 · National Institutes of Health
Member, Site Visit Evaluation Committee for Dept. of Genetics and Genomics
2008 · Institut Pasteur
Faculty Leader, Cellular and Molecular Biosciences Faculty, School of Life Sciences
2007-2012 · Arizona State University
Member, Executive Committee, School of Life Sciences
2007-2012 · Arizona State University
Member, Topics in Bacterial Pathogenesis Study Section
2006-2008 · National Institutes of Health
Councilor, Division U (Mycobacteriology)
2004-2006 · American Society for Microbiology
Alternate Councilor, Division U (Mycobacteriology)
2002-2004 · American Society for Microbiology
Member, Bacteriology and Mycology Study Section I
1995-1999 · National Institutes of Health
1991-2002 · Editorial Board, Infection and Immunity
Chair, Division U (Mycobacteriology)
1991-1992 · American Society for Microbiology
1990-2000 · International Committee on Systematic Bacteriology
Chair-elect, Division U (Mycobacteriology)
1990-1991 · American Society for Microbiology
1986-1991 · Leprosy Panel of the Joint U.S.-Japan Cooperative Medical Sciences Program
President's Fellowship
1969 · American Society for Microbiology

Teaching Profile

Courses Taught
MCB7979 Advanced Research
GMS7979 Advanced Research
VME6464 Molecular Pathogenesis

Research Profile

Tuberculosis has been a scourge to humankind since prehistoric times and remains a serious and significant infectious disease to this day. The World Health Organization estimates that one-third of the world’s population is infected by Mycobacterium tuberculosis, the causative agent of TB, with 9.6 million new cases diagnosed in 2014. Although not all individuals who are infected develop disease, among those who do, more than 1.4 million die each year, making TB the most deadly disease caused by a single bacterial pathogen. Tuberculosis is highly prevalent in those parts of the world where HIV/AIDS occurs and the two infections result in a deadly synergism, with devastating effects on the infected individuals and on the societies in which they live. Morbidity due to chronic respiratory and diarrheal diseases in infancy coupled with malnutrition preclude normal mental development necessary for individuals to achieve self-sufficiency by those who survive to age five.

Tuberculosis can be effectively treated with chemotherapy, but involves a regimen lasting six or more months. Because of the duration of treatment, patient compliance becomes a significant problem. One consequence of non-compliance is the development of drug-resistant strains. In recent years, there has been an increasing number of cases of TB caused by M. tuberculosis strains that are resistant to two or more of the first-line antibiotics used for treatment (multi-drug resistant or MDR strains) and even more alarmingly, strains that are resistant to all of the first-line drugs, plus three or more second-line drugs (extensively drug-resistant or XDR strains). Disease caused by MDR or XDR strains is difficult to impossible to treat, especially in areas of the world with limited access to medical care or antibiotics.

Although there is a vaccine against M. tuberculosis (M. bovis BCG) that is used in many parts of the world to protect infants and young children from serious complications of TB, protection is not long-lasting and by the time individuals reach adolescence, they are fully susceptible to infection. Thus, there is a real need for a better vaccine against M. tuberculosis, preferably one that will confer long-lasting protection against infection. The literature is replete with documentation of benefits that could accrue either by widespread use of existing vaccines against numerous bacterial and viral pathogens or by development of new safe, efficacious vaccines.

The Clark-Curtiss research group currently has two foci of research interests:

(1) Understanding mechanisms of M. tuberculosis pathogenesis through (a) analyses of M. tuberculosis gene expression, (b) identification of operational metabolic pathways during growth in human macrophages and dendritic cells and (c) regulation of gene expression.

To address the first research focus, we identified genes of M. tuberculosis that are expressed at different times after infection of cultured human macrophages, enabling us to identify metabolic pathways that are functional at those times. We have also characterized several classes of regulatory systems that control gene expression, both in vivo and in vitro (two-component regulatory systems, serine-threonine protein kinases and toxin-anti-toxin regulatory modules).

(2) Development of an effective vaccine against M. tuberculosis using recombinant attenuated Salmonella vaccine delivery systems producing M. tuberculosis antigens.

Based on the belief that immunization to protect individuals from infection is superior to the continued development of new antibiotics to combat bacterial pathogens that inevitably acquire resistance to currently available or newly designed antibiotics, we are using recombinant attenuated Salmonella vectors as vaccines (RASVs) to deliver M. tuberculosis antigens to elicit protective immune responses. We use RASVs because (a) Salmonella can elicit mucosal, antibody and cell-mediated immune responses in immunized individuals, (b) much is known about the genetics and physiology of Salmonella, which enables us to rationally design RASVs that are completely attenuated, but can target specific organ, cells and cellular compartments to enhance immune responses and (c) RASVs can be delivered orally, thereby precluding the use of needles or need for refrigeration for transportation of the vaccines to remote geographic locations.

We have constructed RASVs that display regulated delayed lysis and regulated delayed antigen synthesis following immunization. We have introduced plasmids with genes encoding three immunodominant antigens of M. tuberculosis (Early secreted antigenic target 6 kDa [ESAT-6], culture filtrate protein 10 [CFP-10] and Antigen 85A (Ag85A) into the RASVs and used these RASV-M. tuberculosis constructs to orally immunize mice. Mice immunized with RASVs producing these three M. tuberculosis antigens have been protected as well as or slightly better than mice immunized subcutaneously with M. bovis BCG against aerosol infection with virulent M. tuberculosis. We have demonstrated that the RASV- M. tuberculosis vaccine elicits significant antibody and cellular immune responses that contribute to protection against M. tuberculosis infection. We continue to modify our RASV strains to improve their immunogenic potential and we are evaluating nine other M. tuberculosis antigens for possible inclusion to further enhance our RASV-M. tuberculosis vaccine constructs.

Areas of Interest
  • Bacterial pathogenesis
  • Host-pathogen interaction
  • Mycobacterium Tuberculosis
  • Regulation of Gene Expression
  • Tuberculosis
  • vaccines


Mucosal Delivery of a Self-destructing Salmonella-Based Vaccine Inducing Immunity Against Eimeria.
Avian diseases. 64(3):254-268 [DOI] 10.1637/aviandiseases-D-19-00159. [PMID] 33112952.
Interplay of PhoP and DevR response regulators defines expression of the dormancy regulon in virulent Mycobacterium tuberculosis
Journal of Biological Chemistry. 293(42):16413-16425 [DOI] 10.1074/jbc.RA118.004331.
Salmonella Vaccines: Conduits for Protective Antigens.
Journal of immunology (Baltimore, Md. : 1950). 200(1):39-48 [DOI] 10.4049/jimmunol.1600608. [PMID] 29255088.
Erratum to: The Mycobacterium tuberculosis relBE toxin: antitoxin genes are stress-responsive modules that regulate growth through translation inhibition.
Journal of microbiology (Seoul, Korea). 53(12) [DOI] 10.1007/s12275-015-0741-3. [PMID] 26626358.
Mycobacterium tuberculosis response regulators, DevR and NarL, interact in vivo and co-regulate gene expression during aerobic nitrate metabolism.
The Journal of biological chemistry. 290(13):8294-309 [DOI] 10.1074/jbc.M114.591800. [PMID] 25659431.
The Mycobacterium tuberculosis relBE toxin:antitoxin genes are stress-responsive modules that regulate growth through translation inhibition.
Journal of microbiology (Seoul, Korea). 53(11):783-95 [DOI] 10.1007/s12275-015-5333-8. [PMID] 26502963.
Making Common Sense of Vaccines: An Example of Discussing the Recombinant Attenuated Salmonella Vaccine with the Public.
Nanoethics. 8(2):179-185 [PMID] 25152775.
Utilizing Salmonella for antigen delivery: the aims and benefits of bacterial delivered vaccination.
Expert review of vaccines. 12(4):345-7 [DOI] 10.1586/erv.13.7. [PMID] 23560914.
Live attenuated Salmonella vaccines against Mycobacterium tuberculosis with antigen delivery via the type III secretion system.
Infection and immunity. 80(2):798-814 [DOI] 10.1128/IAI.05525-11. [PMID] 22144486.
Live attenuated Salmonella vaccines displaying regulated delayed lysis and delayed antigen synthesis to confer protection against Mycobacterium tuberculosis.
Infection and immunity. 80(2):815-31 [DOI] 10.1128/IAI.05526-11. [PMID] 22144485.
Mycobacterium tuberculosis protein kinase K enables growth adaptation through translation control.
Journal of bacteriology. 194(16):4184-96 [DOI] 10.1128/JB.00585-12. [PMID] 22661693.
The prrAB two-component system is essential for Mycobacterium tuberculosis viability and is induced under nitrogen-limiting conditions.
Journal of bacteriology. 194(2):354-61 [DOI] 10.1128/JB.06258-11. [PMID] 22081401.
Turning self-destructing Salmonella into a universal DNA vaccine delivery platform.
Proceedings of the National Academy of Sciences of the United States of America. 109(47):19414-9 [DOI] 10.1073/pnas.1217554109. [PMID] 23129620.
Mg2+ facilitates leader peptide translation to induce riboswitch-mediated transcription termination.
The EMBO journal. 30(8):1485-96 [DOI] 10.1038/emboj.2011.66. [PMID] 21399613.
Mycobacterium tuberculosis protein kinase K confers survival advantage during early infection in mice and regulates growth in culture and during persistent infection: implications for immune modulation.
Microbiology (Reading, England). 156(Pt 9):2829-2841 [DOI] 10.1099/mic.0.040675-0. [PMID] 20522497.
DevR-mediated adaptive response in Mycobacterium tuberculosis H37Ra: links to asparagine metabolism.
Tuberculosis (Edinburgh, Scotland). 89(2):169-74 [DOI] 10.1016/ [PMID] 19217827.
Three Mycobacterium tuberculosis Rel toxin-antitoxin modules inhibit mycobacterial growth and are expressed in infected human macrophages.
Journal of bacteriology. 191(5):1618-30 [DOI] 10.1128/JB.01318-08. [PMID] 19114484.
The Mycobacterium tuberculosis TrcR response regulator represses transcription of the intracellularly expressed Rv1057 gene, encoding a seven-bladed beta-propeller.
Journal of bacteriology. 188(1):150-9 [PMID] 16352831.
Global expression analysis of two-component system regulator genes during Mycobacterium tuberculosis growth in human macrophages.
FEMS microbiology letters. 236(2):341-7 [PMID] 15251217.
Molecular genetics of Mycobacterium tuberculosis pathogenesis.
Annual review of microbiology. 57:517-49 [PMID] 14527290.
Expression, autoregulation, and DNA binding properties of the Mycobacterium tuberculosis TrcR response regulator.
Journal of bacteriology. 184(8):2192-203 [PMID] 11914351.
Microbial gene expression elucidated by selective capture of transcribed sequences (SCOTS).
Methods in enzymology. 358:108-22 [PMID] 12474381.
Mycobacterium avium genes expressed during growth in human macrophages detected by selective capture of transcribed sequences (SCOTS).
Infection and immunity. 70(7):3714-26 [PMID] 12065514.
Identification of Mycobacterium tuberculosis RNAs synthesized in response to phagocytosis by human macrophages by selective capture of transcribed sequences (SCOTS).
Proceedings of the National Academy of Sciences of the United States of America. 96(20):11554-9 [PMID] 10500215.
Identification of virulence determinants in pathogenic mycobacteria.
Current topics in microbiology and immunology. 225:57-79 [PMID] 9386328.
Cloning, sequencing, and expression of the mig gene of Mycobacterium avium, which codes for a secreted macrophage-induced protein.
Infection and immunity. 65(11):4548-57 [PMID] 9353032.
A Mycobacterium leprae gene encoding a fibronectin binding protein is used for efficient invasion of epithelial cells and Schwann cells.
Infection and immunity. 63(7):2652-7 [PMID] 7790081.
Immunological and functional characterization of Mycobacterium leprae protein antigens: an overview.
Molecular microbiology. 18(5):791-800 [PMID] 8825083.
Characterization of a Mycobacterium leprae antigen related to the secreted Mycobacterium tuberculosis protein MPT32.
Infection and immunity. 62(1):252-8 [PMID] 8262636.
Induction of Mycobacterium avium gene expression following phagocytosis by human macrophages.
Infection and immunity. 62(2):476-83 [PMID] 7507894.
Leprosy vaccine.
Nature. 368(6472) [PMID] 7908414.
A Mycobacterium leprae-specific gene encoding an immunologically recognized 45 kDa protein.
Molecular microbiology. 10(4):829-38 [PMID] 7934845.
Detection of genes expressed by Mycobacterium avium growing in human macrophages.
Infectious agents and disease. 2(4):279-81 [PMID] 8173810.
Escherichia coli heat-labile toxin subunit B fusions with Streptococcus sobrinus antigens expressed by Salmonella typhimurium oral vaccine strains: importance of the linker for antigenicity and biological activities of the hybrid proteins.
Infection and immunity. 61(3):1004-15 [PMID] 8432584.
Localization of the steroid 1-dehydrogenase in Rhodococcus erythropolis IMET 7030 by immunoelectron microscopy.
Journal of basic microbiology. 32(1):65-71 [PMID] 1527710.
Molecular and immunological analysis of a fibronectin-binding protein antigen secreted by Mycobacterium leprae.
Molecular microbiology. 6(2):153-63 [PMID] 1532043.
Overexpression of a Rhodococcus erythropolis protein in Escherichia coli with immunological identity to the Rhodococcus steroid 1-dehydrogenase. Immunoelectron microscopic localization and electrophoretic studies.
Journal of basic microbiology. 32(4):269-77 [PMID] 1460569.
Cloning and characterization of the Mycobacterium leprae putative ribosomal RNA promoter in Escherichia coli.
Gene. 98(1):123-7 [PMID] 1707388.
Identification of Mycobacterium leprae antigens from a cosmid library: characterization of a 15-kilodalton antigen that is recognized by both the humoral and cellular immune systems in leprosy patients.
Infection and immunity. 59(11):4117-24 [PMID] 1840579.
Identification and characterization of antigenic determinants of Mycobacterium leprae that react with antibodies in sera of leprosy patients.
Infection and immunity. 58(5):1327-36 [PMID] 1691143.
Protein antigens of Mycobacterium leprae.
Research in microbiology. 141(7-8):859-71 [PMID] 2101476.
A species-specific repetitive sequence in Mycobacterium leprae DNA.
The Journal of infectious diseases. 159(1):7-15 [PMID] 2642523.
Characterization and taxonomic implications of the rRNA genes of Mycobacterium leprae.
Journal of bacteriology. 171(1):70-3 [PMID] 2644213.
Conservation of genomic sequences among isolates of Mycobacterium leprae.
Journal of bacteriology. 171(9):4844-51 [PMID] 2570057.
Genetic relationships among Mycobacterium leprae, Mycobacterium tuberculosis, and candidate leprosy vaccine strains determined by DNA hybridization: identification of an M. leprae-specific repetitive sequence.
Infection and immunity. 57(5):1535-41 [PMID] 2565292.
Benefits of recombinant DNA technology for the study of Mycobacterium leprae.
Current topics in microbiology and immunology. 138:61-79 [PMID] 3058391.
Expression of Mycobacterium leprae genes from a Streptococcus mutans promoter in Escherichia coli K-12.
Proceedings of the National Academy of Sciences of the United States of America. 83(6):1926-30 [PMID] 2869492.
In vivo repackaging of recombinant cosmid molecules for analyses of Salmonella typhimurium, Streptococcus mutans, and mycobacterial genomic libraries.
Infection and immunity. 52(1):101-9 [PMID] 2937735.
Genes for the major protein antigens of the leprosy parasite Mycobacterium leprae.
Nature. 316(6027):450-2 [PMID] 3894979.
Molecular analysis of DNA and construction of genomic libraries of Mycobacterium leprae.
Journal of bacteriology. 161(3):1093-102 [PMID] 3882664.
Analysis of recombinant DNA using Escherichia coli minicells.
Methods in enzymology. 101:347-62 [PMID] 6350817.


Jun 2016 – Jan 2017
Yersinia pseudotuberculosis-based vaccines for plague and yersiniosis
Role: Project Manager
Aug 2015 – May 2020
Recombinant Attenuated Salmonella Vaccines for Humans
Role: Project Manager
Aug 2015 – Apr 2017
Recombinant Attenuated bacterial vaccines against
Role: Project Manager

Contact Details

(352) 294-5481
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