Limits...
Active immunization against complement factor C5a: a new therapeutic approach for Alzheimer's disease.

Landlinger C, Oberleitner L, Gruber P, Noiges B, Yatsyk K, Santic R, Mandler M, Staffler G - J Neuroinflammation (2015)

Bottom Line: Especially, complement factor C5a and its receptor have been found to be up-regulated in microglia in the immediate surroundings of cerebral amyloid plaques and blocking of C5aR resulted in a reduction of pathological markers in a model of AD.Both C5a-targeting vaccines were highly immunogenic and induced sustained antibody titers against C5a.C5a-peptide vaccines represent a safe and well-tolerated immunotherapy, which is able to induce a strong and specific immune response against the pro-inflammatory molecule C5a.

View Article: PubMed Central - PubMed

Affiliation: AFFiRiS AG, Karl-Farkas-Gasse 22, Vienna, 1030, Austria. christine.landlinger@affiris.com.

ABSTRACT

Background: Alzheimer's disease (AD) is the most common neurodegenerative disease characterized by neuronal loss due to amyloid beta aggregations, neurofibrillary tangles, and prominent neuroinflammation. Recently, interference with neuroinflammation as a new therapeutic approach for AD treatment gained great interest. Microglia cells, one of the major contributors in neuroinflammation, are activated in response to misfolded proteins such as amyloid β and cell debris leading to a sustained release of pro-inflammatory mediators. Especially, complement factor C5a and its receptor have been found to be up-regulated in microglia in the immediate surroundings of cerebral amyloid plaques and blocking of C5aR resulted in a reduction of pathological markers in a model of AD. Here, we investigate the effect of active vaccination against the complement factor C5a to interfere with neuroinflammation and neuropathologic alterations in a mouse model of AD.

Methods: Short antigenic peptides AFF1 and AFF2, which mimic a C-terminal epitope of C5a, were selected and formulated to vaccines. These vaccines are able to induce a highly specific antibody response to the target protein C5a. Tg2576 mice, a common model of AD, were immunized with these two C5a-peptide vaccines and the induced immune response toward C5a was analyzed by ELISA and Western blot analysis. The influence on memory retention was assessed by a contextual fear conditioning test. Microglia activation and amyloid plaque deposition in the brain was visualized by immunohistochemistry.

Results: Both C5a-targeting vaccines were highly immunogenic and induced sustained antibody titers against C5a. Tg2576 mice vaccinated at early stages of the disease showed significantly improved contextual memory accompanied by the reduction of microglia activation in the hippocampus and cerebral amyloid plaque load compared to control mice. Late-stage immunization also showed a decrease in the number of activated microglia, and improved memory function, however, had no influence on the amyloid β load.

Conclusion: C5a-peptide vaccines represent a safe and well-tolerated immunotherapy, which is able to induce a strong and specific immune response against the pro-inflammatory molecule C5a. In a mouse model of AD, C5a-peptide vaccines reduce microglia activation and thus neuroinflammation, which is supposed to lead to reduced neuronal dysfunction and AD symptomatic decline.

No MeSH data available.


Related in: MedlinePlus

C5a-peptide vaccines are immunogenic and induce a target-specific antibody response in wt mice. 129S6 wt mice were immunized 4 times with AFF1- (n = 12) and AFF2- (n = 12) containing vaccines starting at the age of 11 months. Control mice (n = 12) were immunized 4 times with a KLH-only vaccine. Plasma samples obtained after the last immunization were analyzed by ELISA. a The mean IgG antibody titers (ODmax/2) against the injected peptides AFF1 and AFF2 and against an irrelevant peptide. b The mean titers against the target protein C5a present in its two forms C5a desARG and C5a ARG. Bars represent the group means ± SEM of n animals
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4537556&req=5

Fig1: C5a-peptide vaccines are immunogenic and induce a target-specific antibody response in wt mice. 129S6 wt mice were immunized 4 times with AFF1- (n = 12) and AFF2- (n = 12) containing vaccines starting at the age of 11 months. Control mice (n = 12) were immunized 4 times with a KLH-only vaccine. Plasma samples obtained after the last immunization were analyzed by ELISA. a The mean IgG antibody titers (ODmax/2) against the injected peptides AFF1 and AFF2 and against an irrelevant peptide. b The mean titers against the target protein C5a present in its two forms C5a desARG and C5a ARG. Bars represent the group means ± SEM of n animals

Mentions: Peptides (AFFITOPE®s) mimicking the C-terminal neo-epitope of murine C5a were designed, formulated, and tested in 129S6 wt mice for their immunogenicity and ability to induce antibodies against the endogenous target protein C5a (Fig. 1). C5a is present in two different forms, the highly active C5a ARG which becomes rapidly metabolized by a carboxypeptidase to the less active though more stable C5a molecule without the C-terminal arginine, C5a desARG. As the relevance of the two different forms of C5a in neuro-inflammatory disease is still unknown, different C5a-targeting peptides (AFFITOPE®s), AFF1 and AFF2, have been selected for in vivo testing. Both AFF1- and AFF2-containing vaccines elicited similarly high titers of approximately 1/50.000 against their antigenic peptide moiety (Fig. 1a). No cross-reactivity against an unrelated irrelevant peptide was observed (Fig. 1a). However, their reactivity against the different forms of the target protein differed. AFF1-containing vaccine mounted higher antibody titers against C5a desARG, whereas AFF2-containing vaccine primarily induced a strong immune response against the more active molecule, C5a ARG (Fig. 1b). As expected, control immunized mice did not show any immune response against C5a ARG and C5a desARG (Fig. 1b).Fig. 1


Active immunization against complement factor C5a: a new therapeutic approach for Alzheimer's disease.

Landlinger C, Oberleitner L, Gruber P, Noiges B, Yatsyk K, Santic R, Mandler M, Staffler G - J Neuroinflammation (2015)

C5a-peptide vaccines are immunogenic and induce a target-specific antibody response in wt mice. 129S6 wt mice were immunized 4 times with AFF1- (n = 12) and AFF2- (n = 12) containing vaccines starting at the age of 11 months. Control mice (n = 12) were immunized 4 times with a KLH-only vaccine. Plasma samples obtained after the last immunization were analyzed by ELISA. a The mean IgG antibody titers (ODmax/2) against the injected peptides AFF1 and AFF2 and against an irrelevant peptide. b The mean titers against the target protein C5a present in its two forms C5a desARG and C5a ARG. Bars represent the group means ± SEM of n animals
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4537556&req=5

Fig1: C5a-peptide vaccines are immunogenic and induce a target-specific antibody response in wt mice. 129S6 wt mice were immunized 4 times with AFF1- (n = 12) and AFF2- (n = 12) containing vaccines starting at the age of 11 months. Control mice (n = 12) were immunized 4 times with a KLH-only vaccine. Plasma samples obtained after the last immunization were analyzed by ELISA. a The mean IgG antibody titers (ODmax/2) against the injected peptides AFF1 and AFF2 and against an irrelevant peptide. b The mean titers against the target protein C5a present in its two forms C5a desARG and C5a ARG. Bars represent the group means ± SEM of n animals
Mentions: Peptides (AFFITOPE®s) mimicking the C-terminal neo-epitope of murine C5a were designed, formulated, and tested in 129S6 wt mice for their immunogenicity and ability to induce antibodies against the endogenous target protein C5a (Fig. 1). C5a is present in two different forms, the highly active C5a ARG which becomes rapidly metabolized by a carboxypeptidase to the less active though more stable C5a molecule without the C-terminal arginine, C5a desARG. As the relevance of the two different forms of C5a in neuro-inflammatory disease is still unknown, different C5a-targeting peptides (AFFITOPE®s), AFF1 and AFF2, have been selected for in vivo testing. Both AFF1- and AFF2-containing vaccines elicited similarly high titers of approximately 1/50.000 against their antigenic peptide moiety (Fig. 1a). No cross-reactivity against an unrelated irrelevant peptide was observed (Fig. 1a). However, their reactivity against the different forms of the target protein differed. AFF1-containing vaccine mounted higher antibody titers against C5a desARG, whereas AFF2-containing vaccine primarily induced a strong immune response against the more active molecule, C5a ARG (Fig. 1b). As expected, control immunized mice did not show any immune response against C5a ARG and C5a desARG (Fig. 1b).Fig. 1

Bottom Line: Especially, complement factor C5a and its receptor have been found to be up-regulated in microglia in the immediate surroundings of cerebral amyloid plaques and blocking of C5aR resulted in a reduction of pathological markers in a model of AD.Both C5a-targeting vaccines were highly immunogenic and induced sustained antibody titers against C5a.C5a-peptide vaccines represent a safe and well-tolerated immunotherapy, which is able to induce a strong and specific immune response against the pro-inflammatory molecule C5a.

View Article: PubMed Central - PubMed

Affiliation: AFFiRiS AG, Karl-Farkas-Gasse 22, Vienna, 1030, Austria. christine.landlinger@affiris.com.

ABSTRACT

Background: Alzheimer's disease (AD) is the most common neurodegenerative disease characterized by neuronal loss due to amyloid beta aggregations, neurofibrillary tangles, and prominent neuroinflammation. Recently, interference with neuroinflammation as a new therapeutic approach for AD treatment gained great interest. Microglia cells, one of the major contributors in neuroinflammation, are activated in response to misfolded proteins such as amyloid β and cell debris leading to a sustained release of pro-inflammatory mediators. Especially, complement factor C5a and its receptor have been found to be up-regulated in microglia in the immediate surroundings of cerebral amyloid plaques and blocking of C5aR resulted in a reduction of pathological markers in a model of AD. Here, we investigate the effect of active vaccination against the complement factor C5a to interfere with neuroinflammation and neuropathologic alterations in a mouse model of AD.

Methods: Short antigenic peptides AFF1 and AFF2, which mimic a C-terminal epitope of C5a, were selected and formulated to vaccines. These vaccines are able to induce a highly specific antibody response to the target protein C5a. Tg2576 mice, a common model of AD, were immunized with these two C5a-peptide vaccines and the induced immune response toward C5a was analyzed by ELISA and Western blot analysis. The influence on memory retention was assessed by a contextual fear conditioning test. Microglia activation and amyloid plaque deposition in the brain was visualized by immunohistochemistry.

Results: Both C5a-targeting vaccines were highly immunogenic and induced sustained antibody titers against C5a. Tg2576 mice vaccinated at early stages of the disease showed significantly improved contextual memory accompanied by the reduction of microglia activation in the hippocampus and cerebral amyloid plaque load compared to control mice. Late-stage immunization also showed a decrease in the number of activated microglia, and improved memory function, however, had no influence on the amyloid β load.

Conclusion: C5a-peptide vaccines represent a safe and well-tolerated immunotherapy, which is able to induce a strong and specific immune response against the pro-inflammatory molecule C5a. In a mouse model of AD, C5a-peptide vaccines reduce microglia activation and thus neuroinflammation, which is supposed to lead to reduced neuronal dysfunction and AD symptomatic decline.

No MeSH data available.


Related in: MedlinePlus