Mononuclear Phagocytes & HIV Infection Guido …Mononuclear Phagocytes & HIV Infection Guido Poli, M.D. The screen versions of these slides have full details of copyright and acknowledgements

Mononuclear Phagocytes & HIV InfectionGuido Poli, M.D.

1The screen versions of these slides have full details of copyright and acknowledgements

1

Mononuclear Phagocytes & HIV Infection

Guido Poli, M.D.AIDS ImmunoPathogenesis Unit, San Raffaele

University & Scientific Institute, Milano

2

No preventive vaccine is yet available

The HIV pandemic - 2010

3

HIV structure

• Secondly discovered human pathogenic retrovirus (first: HTLV-1) in 1983 (Nobel Prize in 2008)

• Etiological agent of the Acquired Immunodeficiency Syndrome (AIDS)



4

HIV targets cells express CD4 (primary receptor)and CCR5 or CXCR4 (co-receptors)

After: E.A. Berger et al., Nature 391: 240, 1998; P. Lusso, Virology, 273: 228, 2000

5

The HIV life cycle

6

Macrophages as “Trojan horses”of HIV virions



7

CD4+ T lymphocytes• Both R5 and CXCR4-

using HIV

• Acute, cytopathic,depleted in vivo (AIDS)

• Latent infectionin “resting memory” cells

Macrophages• Mostly R5

• Low-absent cytopathicity, prolonged virus production, NOT depleted in vivo

• “Trojan horses”: accumulation of virions in i.c. vacuoles (debated origin)

Main distinctive features of HIV infection of T cells and macrophages

8

Mononuclear phagocytes; differentiation & HIV infection

HIV

? ? ?

9 Science, 1988

HIV infects bone marrow MP precursors in vitro

?



10

HIV infects bone marrow MP precursors in vivo

?

11 Clin. Exp. Immunol. 1985

HIV infection affects the function of circulating monocytes

?

HIV

12

HIV infects circulating monocytes

?

HIV



13

• HIV & the Brain

• HIV & Intestinal Macrophages

HIV & tissue macrophages: heterogeneous susceptibility to infection & viral reservoirs

?

14 JAMA, 1986

HIV & the brain: macrophages and microglia are the dominant infected cells

15 After: P. Smith et al., J. Leuk. Biol., 2003

• Intestinal macrophages are CD4+, but devoid of the expression of the virus entry co-receptors CXCR4 and CCR5

Intestinal (resident) macrophages do not express HIV entry Co-R...




...and are not infectible by HIV...

• Intestinal macrophages are resistant to both R5 and X4 virus infection, as exemplified by the BaL and IIIB isolates, that can efficiently propagate in intestinal lymphocytes, as measured by an ELISA assay specific for the presence of the p24 Gag antigen of HIV in culture supernatants


Intestinal (resident) macrophages do not express HIV entry Co-R...

18

HIV replication in myelo-monocytic cell lines; What can we learn?



19

Promonocytic U937 & its chronically infected derivative U1 cell lines

20

Promonocytic U937 & its chronically infected derivative U1 cell lines (2)

21 L. Cassetta et al., AIDS, 2009

HMGB1 selectively inhibits X4 HIV-1 replication in minus, but not plus U937 cell clones



22 L. Cassetta et al., AIDS, 2009

Differential expression of HMGB1-Rin minus and plus U937 cell clones

23 Anna Kajaste-Runitski et al., J. Virol. 2011

Only minus U937 cell clones express TRIM22, an intracellular factor

inhibiting HIV transcription

24 After: T.M. Folks et al., Science, 1987; J. Immunol. 1988

Promonocytic U937 & its chronically infected derivative U1 cell lines



25 After: G. Poli et al., Science 1989; P. Biswas et al., J. Exp. Med. 1992

Differential effect of IFN-a and IFN-gon HIV virion production from Mø

26After: *M. Alfano et al., P.N.A.S., 2002;

**L. Fantuzzi et al., Blood 2003; ***M. Alfano et al., Blood 2009

Differential effect of IFN-a and IFN-gon HIV virion production from Mø (2)

Urokinase-Type Plasminogen Activator

(uPA)*

CCL2/MCP1**

Mac1 Integrin***

27

...and the cellular capacity of sustaining virus replication?

Does Mø polarization influencesusceptibility to HIV infection?...



28

Human macrophages can be polarized...

Pro-InflammatoryAnti-Tumor

Anti-Microbial

Anti-InflammatoryTissue Repair

M1

M2

29

R5 HIVInfection

E. Cassol et al., J Immunol 2009

MDM

7 days

D-MEM+FCS/HS

Monocytes

M1

18 h

CD16LOW

M2CD14LOW

Polarization of human monocyte-derived macrophages

30 E. Cassol et al., J Immunol 2009

Days post-infection

RT

activ

ity (c

pm/μ

l) Control

M1

M2a

Both M1 and M2a polarization of human MDM inhibits HIV-1 replication



31

M1 and M2a differentially modulate CD4 expression…

…. and chemokine productionafter polarization

0

1,000

2,000

3,000

4,000

pg/m

l

E. Cassol et al., J Immunol 2009

0 3 705

1015202530354045

CTRM1M2

Days

%C

D4+

MD

M

Functional differences between M1 and M2 human MDM

32

48 h post-infection

Control M1 M2aHIV

DNA

Cop

ies/

2.5x

104C

ells

p=0.006p=0.006

256

512

1,024

2,048

4,096

Actin

Control M1 M2a15010075

50

37

2520

250

7 days p.i.Western blot

for HIV-1 ProteinsE. Cassol et al., J Immunol 2009

Differential inhibitory effects of M1 vs. M2 inhibition of HIV-1 replication

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• In addition to CD4+ T lymphocytes, mononuclear phagocytes (MP) represent a strategic target for HIV infection

• Unlike CD4+ T cells, infected MP (including BM precursors, circulating monocytes and tissue Mø) remain viable, although dysfunctional, and represent pool of either latent or productive infection

• The MP unique feature of being “Trojan horses” of pre-formed mature virions render them one of the most important HIV reservoirs also in individuals receiving anti-retroviral therapy

• Modulation of Mø polarization regulates their susceptibility to infection by HIV-1 and its replicative capacity although these features are transient in vitro

Conclusions



34

EdanaCassol

MassimoAlfano

LucaCassettaElisa

Vicenzi

AIDS immunopathogenesis & viral pathogens & biosafety units, HSR

35

Documents

Mononuclear Phagocytes & HIV Infection Guido …Mononuclear Phagocytes & HIV Infection Guido Poli, M.D. The screen versions of these slides have full details of copyright and acknowledgements