Protists Notes

What are protists?

Protists are single-celled eukaryotic organisms that contain membrane-bound organelles and a nucleus.

Which key examples of protozoan parasites were discussed in the lecture?

Toxoplasma gondii, Plasmodium species, and Trypanosoma brucei.

What is the role of innate immunity?

Innate immunity provides the first rapid response against protozoan parasites and is non-specific.

What cells are components of innate immunity?

Macrophages, dendritic cells, neutrophils, natural killer (NK) cells, and inflammatory cytokines.

How does adaptive immunity differ from innate immunity?

Adaptive immunity is slower but highly specific, involving B cells and T cells.

What is Toxoplasma gondii?

Toxoplasma gondii is an intracellular protozoan parasite that infects many warm-blooded animals.

How can humans become infected with Toxoplasma gondii?

Through contact with cat faeces, contaminated soil, food, water, undercooked meat, congenital transmission, organ transplantation, and unpasteurised milk.

What are tachyzoites?

Tachyzoites are the rapidly dividing form of Toxoplasma gondii responsible for acute infection.

What are bradyzoites?

Bradyzoites are slow-growing forms of Toxoplasma gondii found inside tissue cysts and associated with chronic infection.

What cytokine is crucial for controlling Toxoplasma gondii infection?

IFN-γ is the key cytokine controlling T. gondii infection.

How does Toxoplasma gondii evade the immune system?

By forming dormant bradyzoite cysts and interfering with host signaling pathways.

What severe diseases can Toxoplasma gondii cause in high-risk groups?

Neurological defects and blindness in congenital cases, and toxoplasmic encephalitis in immunocompromised individuals.

What are the symptoms of malaria?

Fever, chills, sweating, headache, nausea, and muscle pain.

What is the main method of transmission for Trypanosoma brucei?

Transmitted by the tsetse fly.

What are the key forms of Trypanosomes?

Slender form (dividing), stumpy form (non-dividing), and metacyclic form (infective).

How do trypanosomes evade the immune system?

Through antigenic variation, frequently changing their surface glycoproteins.

What are the consequences of sequestering infected red blood cells in malaria?

Capillary blockage, severe inflammation, reduced blood flow, and tissue damage.

What is PfEMP1?

A major virulence protein expressed on infected RBCs, encoded by approximately 60 different var genes.

What distinguishes Plasmodium falciparum from other malaria species?

It causes the majority of severe malaria and is associated with cerebral malaria.

What cytokines are involved in the immune response to malaria?

IL-12, IFN-γ, and TNF-α are key cytokines involved.