Consequences of stable transduction and antigen-inducible expression of the human interleukin-7 gene on tetanus-toxoid-specific T cells

Utilizing IL-12, IL-15 and IL-7 as Mucosal Vaccine Adjuvants

In this paper we review and discuss three of the most exciting and promising cytokines for therapeutic intervention and immunomodulation of immune responses including those on mucosal surfaces. The main properties of IL-12, IL-15 and IL-7 are described and the studies utilizing these cytokines as immunomodulators and vaccine adjuvants discussed.

Adjuvant IL-7 or IL-15 overcomes immunodominance and improves survival of the CD8+ memory cell pool

Current models of T cell memory implicate a critical role for IL-7 in the effector-to-memory transition, raising the possibility that IL-7 therapy might enhance vaccine responses. IL-7 has not been studied, to our knowledge, before now for adjuvant activity. We administered recombinant human IL-7 (rhIL-7) to mice during immunization against the male antigen HY and compared these results with those obtained from mice immunized with rhIL-2 and rhIL-15. Administration of rhIL-7 or rhIL-15, but not rhIL-2, increased effector cells directed against these dominant antigens and dramatically enhanced CD8(+) effectors to subdominant antigens. The mechanisms by which the cytokines augmented effector pool generation were multifactorial and included rhIL-7-mediated costimulation and rhIL-15-mediated augmentation of the proliferative burst. The contraction phase of the antigen-specific response was exaggerated in cytokine-treated mice; however, CD8(+) memory pools in rhIL-7- or rhIL-15-treated groups demonstrated superior long-term survival resulting in quantitative advantages that remained long after the cytokines were discontinued, as demonstrated by improved survival after challenge with an HY-expressing tumor undertaken several weeks after cytokine cessation. These results confirm the adjuvant activity of rhIL-15 and demonstrate that rhIL-7 also serves as a potent vaccine adjuvant that broadens immunity by augmenting responses to subdominant antigens and improving the survival of the CD8(+) T cell memory pool.

Genetically modified immunocompetent cells in HIV infection

Even in the era of highly active antiretroviral therapy (HAART), gene therapy (GT) can remain a promising approach for suppressing HIV infection, especially if complemented with other forms of pharmacological and immunological intervention. A large number of vectors and targets have been studied. Here we discuss the potential of genetically treated, antigen-specific immunocompetent cells for adoptive autologous immunotherapy of HIV infection. Cellular therapies with gene-modified CD8 and CD4 lymphocytes are aimed at reconstituting the antigen-specific repertoires that may be deranged as a consequence of HIV infection. Even if complete eradication of HIV from the reservoirs cannot be achieved, reconstitution of cellular immunity specific for opportunistic pathogens and for HIV itself is a desirable option to control progression of HIV infection and AIDS pathogenesis better.

Transcriptional effects of superinfection in HIV chronically infected T cells: studies in dually infected clones

We had previously shown that chronically infected ACH-2 cells (HIVLAI) could be superinfected with HIVRF, that the frequency of superinfection increased with time, and that the transcription of the superinfecting virus exceeded that of the host HIVLAI provirus. In contrast, ACH-2 cells superinfected with a nef-substituted neomycin-resistant (proNEO) provirus were not detectable by DNA polymerase chain reaction (PCR) until geneticin (G418) was added, suggesting that the ability to propagate progressively in culture may be HIV strain specific. Clonal populations of ACH-2 superinfected with proNEO did not demonstrate preferential transcription of the superinfecting virus. However, clones of ACH-2 superinfected with HIVRF (ACH2/RF) showed a preponderance of HIVRF transcripts similar to that seen in bulk populations. Induction of the superinfecting virus by phorbol ester (PMA) occurred more rapidly than the hose provirus and did not equalize transcriptional activity. PCR-derived long terminal repeat (LTR) fragments and Tat cDNAs from A3.01 cells acutely infected with HIVRF or from ACH-2 cells were sequenced and tested for transactivation. The HIVLAI LTR was two to three times more Tat-responsive than the HIVRF LTR. TatRF was two to three times more transcriptionally active on either LTR than TatLAI. Demethylation with 5-azacytidine did not significantly affect HIV expression from the HIVLAI host provirus of superinfected ACH2/RF cell clones. These data suggest that the mechanism of preferential transcription in HIVRF superinfected ACH2/RF may be attributed to the Tat/TAR axis and the effect of the specific locus of host proviral integration.