Effector granules in human T lymphocytes: the luminal proteome of secretory lysosomes from human T cells.

Background: Cytotoxic cells of the immune system have evolved a lysosomal compartment to store and mobilize effector molecules. In T lymphocytes and NK cells, the death factor FasL is one of the characteristic marker proteins of these so-called secretory lysosomes, which combine properties of conventional lysosomes and exocytotic vesicles. Although these vesicles are crucial for immune effector function, their protein content in T cells has so far not been investigated in detail.

Effector granules in human T lymphocytes: proteomic evidence for two distinct species of cytotoxic effector vesicles.

Cytotoxic T cells mobilize effector proteins from prestored lysosomal compartments. Since different activation signals result in alternative routes of target cell killing, utilizing either FasL or the granzyme B/perforin pathway, the existence of distinct forms of effector granules was recently suggested. Applying a protocol for the separation of intact organelles from activated T lymphoblasts, we noticed that FasL-associated secretory lysosomes (SL) segregate from vesicles containing larger amounts of granzymes and granulysin.

Characterization of Phleum pratense pollen extracts by 2-D DIGE and allergen immunoreactivity.

The allergen content of standardized pollen material is crucial for an effective diagnosis and treatment. However, variations in IgE reactivities of allergic patients to different preparations of Phleum pratense pollen have been reported. In order to define and directly compare the allergen composition of pollen preparations provided by different suppliers, a comprehensive proteome analysis of three different timothy grass pollen extracts was performed.

Enrichment and analysis of secretory lysosomes from lymphocyte populations.

Background: In specialized cells, such as mast cells, macrophages, T lymphocytes and Natural Killer cells in the immune system and for instance melanocytes in the skin, secretory lysosomes (SL) have evolved as bifunctional organelles that combine degradative and secretory properties. Mutations in lysosomal storage, transport or sorting molecules are associated with severe immunodeficiencies, autoimmunity and (partial) albinism. In order to analyze the function and content of secretory lysosomes in different cell populations, an efficient enrichment of these organelles is mandatory.

2-D DIGE analysis of the proteome of extracts from peanut variants reveals striking differences in major allergen contents.

Over the last decade, an increasing prevalence of peanut allergies was observed worldwide. Peanuts are meanwhile categorized among the most dangerous food allergens. This is particularly relevant since peanut-derived ingredients are widely used in industrial food production.

2-D DIGE analyses of enriched secretory lysosomes reveal heterogeneous profiles of functionally relevant proteins in leukemic and activated human NK cells.

As part of the innate immune system, natural killer (NK) cells detect and lyse tumor and virus-infected cells without prior antigen-dependent recognition and expansion. To this end, they utilize dual-function organelles that combine properties of conventional lysosomes and exocytotic vesicles. Upon stimulation, these secretory lysosomes (SLs) release their cytotoxic molecules into the immunological synapse.