Can we decrease people’s cat allergies just by changing the cat food?

TeachableMedicalNews article 04302021

Teachable moment in classrooms:

1. immune system chapter – IgE antibodies are made in response to allergens
2. immune system chapter – interactions of antibody with specific targets
3. immune system chapter – elements of anaphylactic reaction

The news item:  Recently several news outlets reported on a new cat food, Purina’s Pro Plan LiveClear, that reduces people’s allergic reaction to cats:

Purina Pro Plan Releasing Cat Food that Can Help Ease Cat Allergies in Humans

Purina Pro Plan LiveClear is designed to safely neutralize Fel d1, the main allergen that causes cat allergies, in your cat’s saliva

The article states that Fel d1 is the major cat allergen, and the new cat food makes cats to carry less of this allergen on their fur.

So, Why Do I Care??

About 10-30% of people are prone to develop allergies to cats. 95% of cat allergies happen because of anaphylactic reaction to the Fel d1 cat allergen. With the popularity of cats in households, any non-invasive method to decrease allergic reactions can have major impact on the quality of life for millions of people in the US alone. In addition, this approach may point the way to similar solution to other allergy problems.

Plain English, Please!!!

First, let’s talk about what is an allergy. Some cells in our immune system are programmed to recognize foreign material we breathe in or we swallow. When immune cells make an IgE antibody in response, then that foreign material is now called an allergen. When the allergen enters the body the second time, the IgE antibody will bind to it like a baseball glove holds a baseball.  Then the allergen-IgE complex will force some white blood cells (mast cells and basophils) to release bioactive chemicals.  In turn, those chemicals cause dilation of small blood vessels in the respiratory and digestive system. In the respiratory system increased mucus secretion, fluid accumulation and local inflammation occurs leading to coughing, runny nose, among other symptoms. All these are part of an anaphylactic/allergic reaction.

Second, let’s talk about how cats cause allergic reaction in humans.  The major cat allergen that cause allergic reaction in people is called Fel d1. It is a protein made mostly by salivary glands of cats, and it is spread onto fur by self-licking. Shed cat hair and dandruff spread the Fel d1 allergen into the environment. In people whose immune cells are genetically programmed to make IgE that reacts with Fel d1, an allergic reaction occurs when cats are around.

Third, let’s talk about how a new cat diet can lessen allergic reactions by humans. Thinking in general terms, one possible way to prevent Fel d1 from reaching a person’s IgE is to cover up the Fel d1 allergen, so it can’t bind to IgE.  The revolutionary component in the new cat food is an antibody that binds to Fel d1. In other words, when cats eat this new food, in the cat’s mouth the baseball glove antibody from the food holds the baseball Fel d1. This way the baseball glove IgE in a person can’t hold the baseball that is already in a baseball glove of the food antibody. In a few weeks’ time the food antibody- Fel d1 complex is spread into the environment, further decreasing interaction with a person’s IgE.