Related Experiment Video

Updated: May 18, 2026

A Method to Assess Fc-mediated Effector Functions Induced by Influenza Hemagglutinin Specific Antibodies
04:47

A Method to Assess Fc-mediated Effector Functions Induced by Influenza Hemagglutinin Specific Antibodies

Published on: February 23, 2018

Immunity to the conserved influenza nucleoprotein reduces susceptibility to secondary bacterial infections

Laura Haynes1, Frank M Szaba, Sheri M Eaton

  • 1Trudeau Institute, Saranac Lake, NY 12983, USA. lhaynes@trudeauinstitute.org

Journal of Immunology (Baltimore, Md. : 1950)
|October 3, 2012
PubMed

Insights

Cross-reactive immunity to influenza can reduce the risk of secondary bacterial infections like pneumonia, even if it doesn't prevent the initial flu. This immunity, even from non-neutralizing vaccines, offers protection against severe bacterial complications.

Area of Science:

  • Immunology
  • Virology
  • Infectious Diseases

Background:

  • Influenza infections lead to over 250,000 annual deaths globally.
  • Secondary bacterial infections, such as pneumonia and otitis media, frequently complicate influenza outbreaks.

Purpose of the Study:

  • To investigate if cross-reactive immunity to influenza can mitigate susceptibility to secondary bacterial infections.
  • To explore the potential of non-neutralizing influenza vaccines in preventing severe bacterial complications.

Main Methods:

  • Mice were infected with one influenza strain (H3N2) and subsequently challenged with a different strain (H1N1).
  • Mice were vaccinated with influenza nucleoprotein and challenged with H1N1 influenza.
  • Susceptibility to secondary infections with Streptococcus pneumoniae (Gram-positive) and Klebsiella pneumoniae (Gram-negative) was assessed.

Main Results:

  • Pre-infection with H3N2 influenza reduced susceptibility to secondary H1N1-induced bacterial infections.
  • Vaccination with influenza nucleoprotein also decreased susceptibility to lethal bacterial infections post-H1N1 challenge.
  • Both T cells and antibodies (Abs) were found to contribute to defense against influenza-induced bacterial diseases.

Conclusions:

  • Cross-reactive immunity, even if non-neutralizing, can protect against secondary bacterial infections following influenza.
  • Influenza nucleoprotein-specific immunity plays a role in suppressing lung inflammation and reducing bacterial susceptibility.
  • Non-neutralizing influenza vaccines may offer public health benefits by preventing severe secondary bacterial diseases.

More Related Videos

A Precise Pathogen Delivery and Recovery System for Murine Models of Secondary Bacterial Pneumonia13:45

A Precise Pathogen Delivery and Recovery System for Murine Models of Secondary Bacterial Pneumonia

Published on: September 21, 2019

An Optimized Hemagglutination Inhibition (HI) Assay to Quantify Influenza-specific Antibody Titers06:34

An Optimized Hemagglutination Inhibition (HI) Assay to Quantify Influenza-specific Antibody Titers

Published on: December 1, 2017

Related Concept Videos

Influenza01:27

Influenza

Influenza is an acute, highly communicable viral disease that affects the respiratory tract and is responsible for seasonal epidemics worldwide. Influenza A is the most prevalent type associated with widespread outbreaks and is subtyped based on two surface glycoproteins: hemagglutinin (H) and neuraminidase (N), as in H1N1. These glycoproteins are essential for viral infectivity, transmission, and immune recognition. Transmission occurs primarily through respiratory droplets and contaminated...
Vaccinations01:51

Vaccinations

Overview
Immune Response Against Viral Pathogens01:29

Immune Response Against Viral Pathogens

The immune system's response to viral infections is a complex and coordinated process involving natural killer (NK) cells, T cell-mediated responses, and antibody-mediated responses.
NK Cells
NK cells are a crucial part of our innate immune system, acting as the first line of defense against viral infections. These cells can recognize and kill infected cells without prior exposure to the virus, effectively slowing down the spread of infection. Additionally, NK cells produce proinflammatory...
Factors Affecting the Risk of Infection01:26

Factors Affecting the Risk of Infection

The hosts' susceptibility to infection depends on several factors. The integrity of the skin and mucous membranes helps protect the body against microbial attacks. When the skin is altered, the chance of infection, limb loss, and even death increases.
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin create...
Immunological Memory01:23

Immunological Memory

Immunological memory, a pivotal pillar of the adaptive immune system, is responsible for the body's ability to remember and respond more swiftly and effectively to previously encountered pathogens. This remarkable feature is what makes vaccines so effective in preventing diseases.
What is Immunological Memory?
Immunological memory is an integral function of the immune system that allows it to recognize and react more rapidly and effectively to pathogens previously encountered. This feature is...
Leaky Scanning02:28

Leaky Scanning

During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA.  Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...