Effects of immunization with the rNfa1 protein on experimental Naegleria fowleri-PAM mice

Area of Science:

• Immunology
• Infectious Diseases
• Neuroscience

Background:

• Naegleria fowleri is a free-living amoeba responsible for primary amoebic meningoencephalitis (PAM), a severe and often fatal human infection.
• Current treatment options for PAM are limited, highlighting the need for effective preventative strategies.

Purpose of the Study:

• To evaluate the efficacy of immunization with recombinant Nfa1 protein in a murine model of Naegleria fowleri infection.
• To assess the immune responses, including antibody and cytokine induction, following Nfa1 protein immunization.

Main Methods:

• BALB/c mice were immunized with recombinant Nfa1 protein via intraperitoneal or intranasal routes.
• Mice were subsequently infected with Naegleria fowleri, and their survival times were monitored.
• Nfa1-specific antibody isotypes (IgG, IgA, IgE) and Th1/regulatory cytokine levels (IFN-γ, IL-10) were analyzed.

Main Results:

• Intraperitoneal and intranasal immunization with rNfa1 protein elicited specific IgG, IgA, and IgE antibody responses.
• The IgG response was predominantly IgG1, with contributions from IgG2b, IgG2a, and IgG3.
• Significant induction of the Th1 cytokine IFN-γ and the regulatory cytokine IL-10 was observed.
• Immunization significantly prolonged the mean survival time of mice challenged with N. fowleri compared to control groups.

Conclusions:

• Immunization with Nfa1 protein can induce protective immune responses against Naegleria fowleri infection in mice.
• The Nfa1 protein holds potential as a candidate for a vaccine against primary amoebic meningoencephalitis.