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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.


Fragment mass spectra of disulfide bonds containing peptides of mhIL-15 after tandem trypsin/Glu-C digestion. The disulfide bonds between cysteine 36–43: 43CFLLE4730SDVHPSC36K37 (a) and cysteine 86–89: 84SGC86KEC89EE91 (b) were shown
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Fig2: Fragment mass spectra of disulfide bonds containing peptides of mhIL-15 after tandem trypsin/Glu-C digestion. The disulfide bonds between cysteine 36–43: 43CFLLE4730SDVHPSC36K37 (a) and cysteine 86–89: 84SGC86KEC89EE91 (b) were shown

Mentions: Sequencing of peptides m/z 441.64 and 747.34 (double charged) confirmed that the purified IL-15 contains disulfide bonds between Cys36- Cys43 and Cys86- Cys89 (Fig. 2a and b). This disulfide arrangement is different to the one described by Pettit for the native protein Cys35-Cys85 and Cys42 -Cys88 [37]. These results confirmed that the major fraction of the human IL-15 previously described by our group [34] was structurally modified with respect to the native protein.Fig. 2


Active immunization with human interleukin-15 induces neutralizing antibodies in non-human primates
Fragment mass spectra of disulfide bonds containing peptides of mhIL-15 after tandem trypsin/Glu-C digestion. The disulfide bonds between cysteine 36–43: 43CFLLE4730SDVHPSC36K37 (a) and cysteine 86–89: 84SGC86KEC89EE91 (b) were shown
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig2: Fragment mass spectra of disulfide bonds containing peptides of mhIL-15 after tandem trypsin/Glu-C digestion. The disulfide bonds between cysteine 36–43: 43CFLLE4730SDVHPSC36K37 (a) and cysteine 86–89: 84SGC86KEC89EE91 (b) were shown
Mentions: Sequencing of peptides m/z 441.64 and 747.34 (double charged) confirmed that the purified IL-15 contains disulfide bonds between Cys36- Cys43 and Cys86- Cys89 (Fig. 2a and b). This disulfide arrangement is different to the one described by Pettit for the native protein Cys35-Cys85 and Cys42 -Cys88 [37]. These results confirmed that the major fraction of the human IL-15 previously described by our group [34] was structurally modified with respect to the native protein.Fig. 2

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.