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Active immunization with human interleukin-15 induces neutralizing antibodies in non-human primates

View Article: PubMed Central - PubMed

ABSTRACT

Background: Interleukin-15 is an immunostimulatory cytokine overexpressed in several autoimmune and inflammatory diseases such as Rheumatoid Arthritis, psoriasis and ulcerative colitis; thus, inhibition of IL-15-induced signaling could be clinically beneficial in these disorders. Our approach to neutralize IL-15 consisted in active immunization with structurally modified human IL-15 (mhIL-15) with the aim to induce neutralizing antibodies against native IL-15. In the present study, we characterized the antibody response in Macaca fascicularis, non-human primates that were immunized with a vaccine candidate containing mhIL-15 in Aluminum hydroxide (Alum), Montanide and Incomplete Freund’s Adjuvant.

Results: Immunization with mhIL-15 elicited a specific antibodies response that neutralized native IL-15-dependent biologic activity in a CTLL-2 cell proliferation assay. The highest neutralizing response was obtained in macaques immunized with mhIL-15 adjuvanted in Alum. This response, which was shown to be transient, also inhibited the activity of simian IL-15 and did not affect the human IL-2-induced proliferation of CTLL-2 cells. Also, in a pool of synovial fluid cells from two Rheumatoid Arthritis patients, the immune sera slightly inhibited TNF-α secretion. Finally, it was observed that this vaccine candidate neither affect animal behavior, clinical status, blood biochemistry nor the percentage of IL-15-dependent cell populations, specifically CD56+ NK and CD8+ T cells.

Conclusion: Our results indicate that vaccination with mhIL-15 induced neutralizing antibodies to native IL-15 in non-human primates. Based on this fact, we propose that this vaccine candidate could be potentially beneficial for treatment of diseases where IL-15 overexpression is associated with their pathogenesis.

No MeSH data available.


Mass spectrum of the intact IL-15 purified from E. coli. Signals corresponding to multi-charged ions are showed for the molecule (B8, B9, B10, B11, B12 and B13) and the myoglobin (A9, A10, A11, A13, A14, A15, A17, A18 and A19) used as an internal standard (Theoretical molecular mass 16951.50 Da)
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Fig1: Mass spectrum of the intact IL-15 purified from E. coli. Signals corresponding to multi-charged ions are showed for the molecule (B8, B9, B10, B11, B12 and B13) and the myoglobin (A9, A10, A11, A13, A14, A15, A17, A18 and A19) used as an internal standard (Theoretical molecular mass 16951.50 Da)

Mentions: The purification process described for the recombinant human IL-15 expressed in E. coli allowed a 95 % of protein purity [34]. This protein contains two disulfide bridges in its structure. Figure 1 depicts the spectrum of multiple charge ions of intact IL-15 obtained by ESI-MS, where a single species of protein outstands with a molecular mass of 12 840.45 ± 0.13 Da. This molecular mass is similar to the expected molecular mass of 12 840.59 Da obtained from the cloned DNA sequence corresponding to the presence of two disulfide bonds and an additional alanine residue in the N-terminal of protein.Fig. 1


Active immunization with human interleukin-15 induces neutralizing antibodies in non-human primates
Mass spectrum of the intact IL-15 purified from E. coli. Signals corresponding to multi-charged ions are showed for the molecule (B8, B9, B10, B11, B12 and B13) and the myoglobin (A9, A10, A11, A13, A14, A15, A17, A18 and A19) used as an internal standard (Theoretical molecular mass 16951.50 Da)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036325&req=5

Fig1: Mass spectrum of the intact IL-15 purified from E. coli. Signals corresponding to multi-charged ions are showed for the molecule (B8, B9, B10, B11, B12 and B13) and the myoglobin (A9, A10, A11, A13, A14, A15, A17, A18 and A19) used as an internal standard (Theoretical molecular mass 16951.50 Da)
Mentions: The purification process described for the recombinant human IL-15 expressed in E. coli allowed a 95 % of protein purity [34]. This protein contains two disulfide bridges in its structure. Figure 1 depicts the spectrum of multiple charge ions of intact IL-15 obtained by ESI-MS, where a single species of protein outstands with a molecular mass of 12 840.45 ± 0.13 Da. This molecular mass is similar to the expected molecular mass of 12 840.59 Da obtained from the cloned DNA sequence corresponding to the presence of two disulfide bonds and an additional alanine residue in the N-terminal of protein.Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: Interleukin-15 is an immunostimulatory cytokine overexpressed in several autoimmune and inflammatory diseases such as Rheumatoid Arthritis, psoriasis and ulcerative colitis; thus, inhibition of IL-15-induced signaling could be clinically beneficial in these disorders. Our approach to neutralize IL-15 consisted in active immunization with structurally modified human IL-15 (mhIL-15) with the aim to induce neutralizing antibodies against native IL-15. In the present study, we characterized the antibody response in Macaca fascicularis, non-human primates that were immunized with a vaccine candidate containing mhIL-15 in Aluminum hydroxide (Alum), Montanide and Incomplete Freund’s Adjuvant.

Results: Immunization with mhIL-15 elicited a specific antibodies response that neutralized native IL-15-dependent biologic activity in a CTLL-2 cell proliferation assay. The highest neutralizing response was obtained in macaques immunized with mhIL-15 adjuvanted in Alum. This response, which was shown to be transient, also inhibited the activity of simian IL-15 and did not affect the human IL-2-induced proliferation of CTLL-2 cells. Also, in a pool of synovial fluid cells from two Rheumatoid Arthritis patients, the immune sera slightly inhibited TNF-α secretion. Finally, it was observed that this vaccine candidate neither affect animal behavior, clinical status, blood biochemistry nor the percentage of IL-15-dependent cell populations, specifically CD56+ NK and CD8+ T cells.

Conclusion: Our results indicate that vaccination with mhIL-15 induced neutralizing antibodies to native IL-15 in non-human primates. Based on this fact, we propose that this vaccine candidate could be potentially beneficial for treatment of diseases where IL-15 overexpression is associated with their pathogenesis.

No MeSH data available.