Erythrocyte Rh antigens increase with red cell age

Ballas, Samir K.; Flynn, John C.; Pauline, Lucy A.; Murphy, Darci L.

doi:10.1002/ajh.2830230104

Cited by 14 publications

(6 citation statements)

References 24 publications

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“…During the life span of a host erythrocyte receptors molecules on the surface are continuously lost or degraded and other receptors like senescence factors become exposed (Killmann, 1964;Berlin and Berk, 1975;Ballas et al, 1986;Clark, 1988). This would mean to the merozoite that more mature erythrocytes have a potentially lower receptor density or contain receptors with reduced affinity.…”

Section: Discussionmentioning

confidence: 99%

Variable expression of the 235 kDa rhoptry protein of Plasmodium yoelii mediate host cell adaptation and immune evasion

Iyer

Amaladoss

Ganesan

et al. 2007

Molecular Microbiology

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SummaryThe severity of infections caused by the malaria parasite Plasmodium is in part due to the rapid multiplication cycles in the blood of an infected individual. A fundamental step in this phenomenon is the invasion of selected erythrocytes of the host by the parasite. The py235 rhoptry protein multigene family of the rodent malaria parasite Plasmodium yoelii has been implicated in mediating host cell selection during erythrocyte invasion and virulence. Here we show using quantitative real-time polymerase chain reaction and Western blot analysis that variations in the amounts of py235 may be a mechanism that the parasite uses to define its host cell repertoire. High levels of py235 expression leads to a wider range of erythrocytes invaded and therefore increased virulence. In contrast, to evade PY235-specific immunity, the parasite downregulates py235 thereby decreasing the host cell repertoire and virulence. These results demonstrate a new mechanism where variations in the amounts of parasite ligand define the parasite host cell repertoire and enable it to evade host immunity.

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Section: Discussionmentioning

confidence: 99%

Variable expression of the 235 kDa rhoptry protein of Plasmodium yoelii mediate host cell adaptation and immune evasion

Iyer

Amaladoss

Ganesan

et al. 2007

Molecular Microbiology

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“…Accord ing to the hyothesis of membrane fluidity-dependent vertical translocation of mem brane proteins an increase in membrane ri gidity may enhance the exposure of mem brane proteins to the extramembranous en vironment [ 107], The observed increased ex posure of Rh antigens in older erythrocytes [108] could be explained by such a mecha nism (though other explanations are also possible). In the studies in which decrease in membrane fluidity was revealed, no signifi cant increase in the membrane cholesterol/ phospholipid ratio was found [45,46] so membrane rigidification has to be accounted for by other mechanisms.…”

Section: Membrane Organizationmentioning

confidence: 90%

Erythrocyte Aging: Physical and Chemical Membrane Changes

Bartosz¹

1991

Gerontology

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The mammalian erythrocyte is an interesting model for studies of membrane aging. Experimental approaches to this problem involve, first of all, comparison of properties of erythrocytes separated by density because red blood cell age correlates with density in principle. Other approaches to study red cell membrane aging, such as hypertransfusion, are also discussed. A number of physical and chemical changes occur in erythrocytes with aging. Crucial to the elucidation of aging mechanisms is to determine which are primary and which are secondary. Immunoglobulin G binding triggers cellular removal and seems necessary for the recognition of senescent erythrocytes. Cellular deformability decreases while fragility to hemolytic factors generally increases and surface charge density does not alter. Perhaps more important are reactions of reactive oxygen species with membrane constituents and subsequent proteolysis. These are implicated as causative factors in red cell aging, immunoglobulin binding and recognition of senescent erythrocytes.

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“…If this were the case, then the predilection of different Plasmodium species to red blood cells of different ages (from reticulocytes to mature and possibly ageing normocytes) might well be accounted for by variations in the density of some receptors at the surface of the red blood cell. The fact that red blood cells are devoid of DNA does not preclude the appearance and increase of surface receptor as the red cell ages, as it is known that age-related alteration of the membrane leads to the exposure of some proteins that were inaccessible in the young red blood cell (Killmann, 1964;Berlin and Berk, 1975;Ballas et al, 1986;Clark, 1988;Woolley et al, 2000). However, experimental approaches that aim to elucidate the nature of the parasite's red blood cell tropism are actually quite restricted.…”

Section: Invasion Of Host Cells By Malaria Parasites 239mentioning

confidence: 99%

Invasion of host cells by malaria parasites: a tale of two protein families

Iyer

Grüner

Rénia

et al. 2007

Molecular Microbiology

128

124

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SummaryMalaria parasites are obligate intracellular parasites whose invasive stages select and invade the unique host cell in which they can develop with exquisite specificity and efficacy. Most studies aimed at elucidating the molecules and the mechanisms implicated in the selection and invasion processes have been conducted on the merozoite, the stage that invades erythrocytes to perpetuate the pathological cycles of parasite multiplication in the blood. Bioinformatic analysis has helped identify the members of two parasite protein families, the reticulocyte-binding protein homologues (RBL) and erythrocyte binding like (EBL), in recently sequenced genomes of different Plasmodium species. In this article we review data from classical studies and gene disruption experiments that are helping to illuminate the role of these proteins in the selection-invasion processes. The manner in which subsets of proteins from each of the families act in concert suggests a model to explain the ability of the parasites to use alternate pathways of invasion. Future perspectives and implications are discussed.

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Erythrocyte Rh antigens increase with red cell age

Cited by 14 publications

References 24 publications

Variable expression of the 235 kDa rhoptry protein of Plasmodium yoelii mediate host cell adaptation and immune evasion

Variable expression of the 235 kDa rhoptry protein of Plasmodium yoelii mediate host cell adaptation and immune evasion

Erythrocyte Aging: Physical and Chemical Membrane Changes

Invasion of host cells by malaria parasites: a tale of two protein families

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